MAX1294AEEI中文资料

M A X471M A X472的中文资料大全(总4页)-本页仅作为预览文档封面，使用时请删除本页-MAX471/MAX472的特点、功能美国美信公司生产的精密高端电流检测放大器是一个系列化产品，有MAX471/MA X472、 MAX4172/MAX4173等。

它们均有一个电流输出端，可以用一个电阻来简单地实现以地为参考点的电流/电压的转换，并可工作在较宽电压内。

MAX471/MAX472具有如下特点：●具有完美的高端电流检测功能；●内含精密的内部检测电阻（MAX471）；●在工作温度范围内，其精度为2%；●具有双向检测指示，可监控充电和放电状态；●内部检测电阻和检测能力为3A，并联使用时还可扩大检测电流范围；●使用外部检测电阻可任意扩展检测电流范围（MAX472）；●最大电源电流为100μA；●关闭方式时的电流仅为5μA；●电压范围为3～36V；●采用8脚DIP/SO/STO三种封装形式。

MAX471/MAX472的引脚排列如图1所示，图2所示为其内部功能框图。

表1为MAX471/MAX472的引脚功能说明。

MAX471的电流增益比已预设为500μA/A，由于2kΩ的输出电阻（ROUT）可产生1V/A的转换，因此±3A时的满度值为3V.用不同的ROUT电阻可设置不同的满度电压。

但对于MAX471，其输出电压不应大于VRS+。

对于MAX472，则不能大于。

MAX471引脚图如图１所示，MAX472引脚图如图２所示。

MAX471/MAX472的引脚功能说明引脚名称功能MAX471MAX47211SHDN关闭端。

正常运用时连接到地。

当此端接高电平时，电源电流小于5μA2，3-RS+内部电流检测电阻电池（或电源端）。

“+”仅指示与SIGN输出有关的流动方向。

封装时已将2和3连在了一起-2空脚-3RG1增益电阻端。

通过增益设置电阻连接到电流检测电阻的电池端44GND地或电池负端55SIGN集电极开路逻辑输出端。

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .General DescriptionThe MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 are low-power transceivers for RS-485 and RS-422 communication. Each part contains one driver and one receiver. The MAX483, MAX487, MAX488, and MAX489feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables,thus allowing error-free data transmission up to 250kbps.The driver slew rates of the MAX481, MAX485, MAX490,MAX491, and MAX1487 are not limited, allowing them to transmit up to 2.5Mbps.These transceivers draw between 120µA and 500µA of supply current when unloaded or fully loaded with disabled drivers. Additionally, the MAX481, MAX483, and MAX487have a low-current shutdown mode in which they consume only 0.1µA. All parts operate from a single 5V supply.Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into a high-imped-ance state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit.The MAX487 and MAX1487 feature quarter-unit-load receiver input impedance, allowing up to 128 MAX487/MAX1487 transceivers on the bus. Full-duplex communi-cations are obtained using the MAX488–MAX491, while the MAX481, MAX483, MAX485, MAX487, and MAX1487are designed for half-duplex applications.________________________ApplicationsLow-Power RS-485 Transceivers Low-Power RS-422 Transceivers Level TranslatorsTransceivers for EMI-Sensitive Applications Industrial-Control Local Area Networks__Next Generation Device Features♦For Fault-Tolerant ApplicationsMAX3430: ±80V Fault-Protected, Fail-Safe, 1/4Unit Load, +3.3V, RS-485 TransceiverMAX3440E–MAX3444E: ±15kV ESD-Protected,±60V Fault-Protected, 10Mbps, Fail-Safe, RS-485/J1708 Transceivers♦For Space-Constrained ApplicationsMAX3460–MAX3464: +5V, Fail-Safe, 20Mbps,Profibus RS-485/RS-422 TransceiversMAX3362: +3.3V, High-Speed, RS-485/RS-422Transceiver in a SOT23 PackageMAX3280E–MAX3284E: ±15kV ESD-Protected,52Mbps, +3V to +5.5V, SOT23, RS-485/RS-422,True Fail-Safe ReceiversMAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,SOT23, RS-855/RS-422 Transmitters ♦For Multiple Transceiver ApplicationsMAX3030E–MAX3033E: ±15kV ESD-Protected,+3.3V, Quad RS-422 Transmitters ♦For Fail-Safe ApplicationsMAX3080–MAX3089: Fail-Safe, High-Speed (10Mbps), Slew-Rate-Limited RS-485/RS-422Transceivers♦For Low-Voltage ApplicationsMAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E: +3.3V Powered, ±15kV ESD-Protected, 12Mbps, Slew-Rate-Limited,True RS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________Selection Table19-0122; Rev 8; 10/03Ordering Information appears at end of data sheet.M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSSupply Voltage (V CC ).............................................................12V Control Input Voltage (RE , DE)...................-0.5V to (V CC + 0.5V)Driver Input Voltage (DI).............................-0.5V to (V CC + 0.5V)Driver Output Voltage (A, B)...................................-8V to +12.5V Receiver Input Voltage (A, B).................................-8V to +12.5V Receiver Output Voltage (RO).....................-0.5V to (V CC +0.5V)Continuous Power Dissipation (T A = +70°C)8-Pin Plastic DIP (derate 9.09mW/°C above +70°C)....727mW 14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)..800mW 8-Pin SO (derate 5.88mW/°C above +70°C).................471mW14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW 8-Pin µMAX (derate 4.1mW/°C above +70°C)..............830mW 8-Pin CERDIP (derate 8.00mW/°C above +70°C).........640mW 14-Pin CERDIP (derate 9.09mW/°C above +70°C).......727mW Operating Temperature RangesMAX4_ _C_ _/MAX1487C_ A...............................0°C to +70°C MAX4__E_ _/MAX1487E_ A.............................-40°C to +85°C MAX4__MJ_/MAX1487MJA...........................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10sec).............................+300°CDC ELECTRICAL CHARACTERISTICS(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.V V IN = -7VV IN = 12V V IN = -7V V IN = 12V Input Current (A, B)I IN2V TH k Ω48-7V ≤V CM ≤12V, MAX487/MAX1487R INReceiver Input Resistance -7V ≤V CM ≤12V, all devices except MAX487/MAX1487R = 27Ω(RS-485), Figure 40.4V ≤V O ≤2.4VR = 50Ω(RS-422)I O = 4mA, V ID = -200mV I O = -4mA, V ID = 200mV V CM = 0V-7V ≤V CM ≤12V DE, DI, RE DE, DI, RE MAX487/MAX1487,DE = 0V, V CC = 0V or 5.25VDE, DI, RE R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4R = 27Ωor 50Ω, Figure 4DE = 0V;V CC = 0V or 5.25V,all devices except MAX487/MAX1487CONDITIONSk Ω12µA ±1I OZRThree-State (high impedance)Output Current at ReceiverV 0.4V OL Receiver Output Low Voltage 3.5V OH Receiver Output High Voltage mV 70∆V TH Receiver Input Hysteresis V -0.20.2Receiver Differential Threshold Voltage-0.2mA 0.25mA-0.81.01.55V OD2Differential Driver Output (with load)V 2V 5V OD1Differential Driver Output (no load)µA±2I IN1Input CurrentV 0.8V IL Input Low Voltage V 2.0V IH Input High Voltage V 0.2∆V OD Change in Magnitude of Driver Common-Mode Output Voltage for Complementary Output States V 0.2∆V OD Change in Magnitude of Driver Differential Output Voltage for Complementary Output States V 3V OC Driver Common-Mode Output VoltageUNITS MINTYPMAX SYMBOL PARAMETERMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________3SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)DC ELECTRICAL CHARACTERISTICS (continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)ns 103060t PHLDriver Rise or Fall Time Figures 6 and 8, R DIFF = 54Ω, C L1= C L2= 100pF ns MAX490M, MAX491M MAX490C/E, MAX491C/E2090150MAX481, MAX485, MAX1487MAX490M, MAX491MMAX490C/E, MAX491C/E MAX481, MAX485, MAX1487Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pF MAX481 (Note 5)Figures 5 and 11, C RL = 15pF, S2 closedFigures 5 and 11, C RL = 15pF, S1 closed Figures 5 and 11, C RL = 15pF, S2 closed Figures 5 and 11, C RL = 15pF, S1 closed Figures 6 and 10, R DIFF = 54Ω,C L1= C L2= 100pFFigures 6 and 8,R DIFF = 54Ω,C L1= C L2= 100pF Figures 6 and 10,R DIFF = 54Ω,C L1= C L2= 100pF CONDITIONS ns 510t SKEW ns50200600t SHDNTime to ShutdownMbps 2.5f MAX Maximum Data Rate ns 2050t HZ Receiver Disable Time from High ns 103060t PLH 2050t LZ Receiver Disable Time from Low ns 2050t ZH Driver Input to Output Receiver Enable to Output High ns 2050t ZL Receiver Enable to Output Low 2090200ns ns 134070t HZ t SKD Driver Disable Time from High |t PLH - t PHL |DifferentialReceiver Skewns 4070t LZ Driver Disable Time from Low ns 4070t ZL Driver Enable to Output Low 31540ns51525ns 31540t R , t F 2090200Driver Output Skew to Output t PLH , t PHL Receiver Input to Output4070t ZH Driver Enable to Output High UNITS MIN TYP MAX SYMBOL PARAMETERFigures 7 and 9, C L = 100pF, S2 closed Figures 7 and 9, C L = 100pF, S1 closed Figures 7 and 9, C L = 15pF, S1 closed Figures 7 and 9, C L = 15pF, S2 closedM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 4_______________________________________________________________________________________SWITCHING CHARACTERISTICS—MAX483, MAX487/MAX488/MAX489(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)SWITCHING CHARACTERISTICS—MAX481/MAX485, MAX490/MAX491, MAX1487 (continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)3001000Figures 7 and 9, C L = 100pF, S2 closed Figures 7 and 9, C L = 100pF, S1 closed Figures 5 and 11, C L = 15pF, S2 closed,A - B = 2VCONDITIONSns 40100t ZH(SHDN)Driver Enable from Shutdown toOutput High (MAX481)nsFigures 5 and 11, C L = 15pF, S1 closed,B - A = 2Vt ZL(SHDN)Receiver Enable from Shutdownto Output Low (MAX481)ns 40100t ZL(SHDN)Driver Enable from Shutdown toOutput Low (MAX481)ns 3001000t ZH(SHDN)Receiver Enable from Shutdownto Output High (MAX481)UNITS MINTYP MAX SYMBOLPARAMETERt PLH t SKEW Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pFt PHL Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pFDriver Input to Output Driver Output Skew to Output ns 100800ns ns 2000MAX483/MAX487, Figures 7 and 9,C L = 100pF, S2 closedt ZH(SHDN)Driver Enable from Shutdown to Output High2502000ns2500MAX483/MAX487, Figures 5 and 11,C L = 15pF, S1 closedt ZL(SHDN)Receiver Enable from Shutdown to Output Lowns 2500MAX483/MAX487, Figures 5 and 11,C L = 15pF, S2 closedt ZH(SHDN)Receiver Enable from Shutdown to Output Highns 2000MAX483/MAX487, Figures 7 and 9,C L = 100pF, S1 closedt ZL(SHDN)Driver Enable from Shutdown to Output Lowns 50200600MAX483/MAX487 (Note 5) t SHDN Time to Shutdownt PHL t PLH , t PHL < 50% of data period Figures 5 and 11, C RL = 15pF, S2 closed Figures 5 and 11, C RL = 15pF, S1 closed Figures 5 and 11, C RL = 15pF, S2 closed Figures 5 and 11, C RL = 15pF, S1 closed Figures 7 and 9, C L = 15pF, S2 closed Figures 6 and 10, R DIFF = 54Ω,C L1= C L2= 100pFFigures 7 and 9, C L = 15pF, S1 closed Figures 7 and 9, C L = 100pF, S1 closed Figures 7 and 9, C L = 100pF, S2 closed CONDITIONSkbps 250f MAX 2508002000Maximum Data Rate ns 2050t HZ Receiver Disable Time from High ns 25080020002050t LZ Receiver Disable Time from Low ns 2050t ZH Receiver Enable to Output High ns 2050t ZL Receiver Enable to Output Low ns ns 1003003000t HZ t SKD Driver Disable Time from High I t PLH - t PHL I DifferentialReceiver SkewFigures 6 and 10, R DIFF = 54Ω,C L1= C L2= 100pFns 3003000t LZ Driver Disable Time from Low ns 2502000t ZL Driver Enable to Output Low ns Figures 6 and 8, R DIFF = 54Ω,C L1= C L2= 100pFns 2502000t R , t F 2502000Driver Rise or Fall Time ns t PLH Receiver Input to Output2502000t ZH Driver Enable to Output High UNITS MIN TYP MAX SYMBOL PARAMETERMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________530002.5OUTPUT CURRENT vs.RECEIVER OUTPUT LOW VOLTAGE525M A X 481-01OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )1.515100.51.02.0203540450.90.1-50-252575RECEIVER OUTPUT LOW VOLTAGE vs.TEMPERATURE0.30.7TEMPERATURE (°C)O U T P U TL O W V O L T A G E (V )500.50.80.20.60.40100125-20-41.5 2.0 3.0 5.0OUTPUT CURRENT vs.RECEIVER OUTPUT HIGH VOLTAGE-8-16M A X 481-02OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )2.5 4.0-12-18-6-14-10-203.54.5 4.83.2-50-252575RECEIVER OUTPUT HIGH VOLTAGE vs.TEMPERATURE3.64.4TEMPERATURE (°C)O U T P UT H I G H V O L T A G E (V )0504.04.63.44.23.83.01001259000 1.0 3.0 4.5DRIVER OUTPUT CURRENT vs.DIFFERENTIAL OUTPUT VOLTAGE1070M A X 481-05DIFFERENTIAL OUTPUT VOLTAGE (V)O U T P U T C U R R E N T (m A )2.0 4.05030806040200.5 1.5 2.53.5 2.31.5-50-2525125DRIVER DIFFERENTIAL OUTPUT VOLTAGEvs. TEMPERATURE1.72.1TEMPERATURE (°C)D I F FE R E N T I A L O U T P U T V O L T A G E (V )751.92.21.62.01.8100502.4__________________________________________Typical Operating Characteristics(V CC = 5V, T A = +25°C, unless otherwise noted.)NOTES FOR ELECTRICAL/SWITCHING CHARACTERISTICSNote 1:All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to deviceground unless otherwise specified.Note 2:All typical specifications are given for V CC = 5V and T A = +25°C.Note 3:Supply current specification is valid for loaded transmitters when DE = 0V.Note 4:Applies to peak current. See Typical Operating Characteristics.Note 5:The MAX481/MAX483/MAX487 are put into shutdown by bringing RE high and DE low. If the inputs are in this state for lessthan 50ns, the parts are guaranteed not to enter shutdown. If the inputs are in this state for at least 600ns, the parts are guaranteed to have entered shutdown. See Low-Power Shutdown Mode section.M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 6___________________________________________________________________________________________________________________Typical Operating Characteristics (continued)(V CC = 5V, T A = +25°C, unless otherwise noted.)120008OUTPUT CURRENT vs.DRIVER OUTPUT LOW VOLTAGE20100M A X 481-07OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )6604024801012140-1200-7-5-15OUTPUT CURRENT vs.DRIVER OUTPUT HIGH VOLTAGE-20-80M A X 481-08OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )-31-603-6-4-2024-100-40100-40-60-2040100120MAX1487SUPPLY CURRENT vs. TEMPERATURE300TEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20608050020060040000140100-50-2550100MAX481/MAX485/MAX490/MAX491SUPPLY CURRENT vs. TEMPERATURE300TEMPERATURE (°C)S U P P L Y C U R R E N T (µA )257550020060040000125100-50-2550100MAX483/MAX487–MAX489SUPPLY CURRENT vs. TEMPERATURE300TEMPERATURE (°C)S U P P L Y C U R R E N T (µA )257550020060040000125MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________7______________________________________________________________Pin DescriptionFigure 1. MAX481/MAX483/MAX485/MAX487/MAX1487 Pin Configuration and Typical Operating CircuitM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487__________Applications InformationThe MAX481/MAX483/MAX485/MAX487–MAX491 and MAX1487 are low-power transceivers for RS-485 and RS-422 communications. The MAX481, MAX485, MAX490,MAX491, and MAX1487 can transmit and receive at data rates up to 2.5Mbps, while the MAX483, MAX487,MAX488, and MAX489 are specified for data rates up to 250kbps. The MAX488–MAX491 are full-duplex trans-ceivers while the MAX481, MAX483, MAX485, MAX487,and MAX1487 are half-duplex. In addition, Driver Enable (DE) and Receiver Enable (RE) pins are included on the MAX481, MAX483, MAX485, MAX487, MAX489,MAX491, and MAX1487. When disabled, the driver and receiver outputs are high impedance.MAX487/MAX1487:128 Transceivers on the BusThe 48k Ω, 1/4-unit-load receiver input impedance of the MAX487 and MAX1487 allows up to 128 transceivers on a bus, compared to the 1-unit load (12k Ωinput impedance) of standard RS-485 drivers (32 trans-ceivers maximum). Any combination of MAX487/MAX1487 and other RS-485 transceivers with a total of 32 unit loads or less can be put on the bus. The MAX481/MAX483/MAX485 and MAX488–MAX491 have standard 12k ΩReceiver Input impedance.Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 8_______________________________________________________________________________________Figure 2. MAX488/MAX490 Pin Configuration and Typical Operating CircuitFigure 3. MAX489/MAX491 Pin Configuration and Typical Operating CircuitMAX483/MAX487/MAX488/MAX489:Reduced EMI and ReflectionsThe MAX483 and MAX487–MAX489 are slew-rate limit-ed, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 12 shows the dri-ver output waveform and its Fourier analysis of a 150kHz signal transmitted by a MAX481, MAX485,MAX490, MAX491, or MAX1487. High-frequency har-monics with large amplitudes are evident. Figure 13shows the same information displayed for a MAX483,MAX487, MAX488, or MAX489 transmitting under the same conditions. Figure 13’s high-frequency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers_______________________________________________________________________________________9_________________________________________________________________Test CircuitsFigure 4. Driver DC Test Load Figure 5. Receiver Timing Test LoadFigure 6. Driver/Receiver Timing Test Circuit Figure 7. Driver Timing Test LoadM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 10_______________________________________________________Switching Waveforms_________________Function Tables (MAX481/MAX483/MAX485/MAX487/MAX1487)Figure 8. Driver Propagation DelaysFigure 9. Driver Enable and Disable Times (except MAX488 and MAX490)Figure 10. Receiver Propagation DelaysFigure 11. Receiver Enable and Disable Times (except MAX488and MAX490)Table 1. TransmittingTable 2. ReceivingLow-Power Shutdown Mode (MAX481/MAX483/MAX487)A low-power shutdown mode is initiated by bringing both RE high and DE low. The devices will not shut down unless both the driver and receiver are disabled.In shutdown, the devices typically draw only 0.1µA of supply current.RE and DE may be driven simultaneously; the parts are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, the parts are guaranteed to enter shutdown.For the MAX481, MAX483, and MAX487, the t ZH and t ZL enable times assume the part was not in the low-power shutdown state (the MAX485/MAX488–MAX491and MAX1487 can not be shut down). The t ZH(SHDN)and t ZL(SHDN)enable times assume the parts were shut down (see Electrical Characteristics ).It takes the drivers and receivers longer to become enabled from the low-power shutdown state (t ZH(SHDN ), t ZL(SHDN)) than from the operating mode (t ZH , t ZL ). (The parts are in operating mode if the –R —E –,DE inputs equal a logical 0,1 or 1,1 or 0, 0.)Driver Output ProtectionExcessive output current and power dissipation caused by faults or by bus contention are prevented by two mechanisms. A foldback current limit on the output stage provides immediate protection against short cir-cuits over the whole common-mode voltage range (see Typical Operating Characteristics ). In addition, a ther-mal shutdown circuit forces the driver outputs into a high-impedance state if the die temperature rises excessively.Propagation DelayMany digital encoding schemes depend on the differ-ence between the driver and receiver propagation delay times. Typical propagation delays are shown in Figures 15–18 using Figure 14’s test circuit.The difference in receiver delay times, | t PLH - t PHL |, is typically under 13ns for the MAX481, MAX485,MAX490, MAX491, and MAX1487 and is typically less than 100ns for the MAX483 and MAX487–MAX489.The driver skew times are typically 5ns (10ns max) for the MAX481, MAX485, MAX490, MAX491, and MAX1487, and are typically 100ns (800ns max) for the MAX483 and MAX487–MAX489.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________1110dB/div0Hz5MHz500kHz/div10dB/div0Hz5MHz500kHz/divFigure 12. Driver Output Waveform and FFT Plot of MAX481/MAX485/MAX490/MAX491/MAX1487 Transmitting a 150kHz SignalFigure 13. Driver Output Waveform and FFT Plot of MAX483/MAX487–MAX489 Transmitting a 150kHz SignalM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 12______________________________________________________________________________________V CC = 5V T A = +25°CV CC = 5V T A = +25°CV CC = 5V T A = +25°CV CC = 5V T A = +25°CFigure 14. Receiver Propagation Delay Test CircuitFigure 15. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver t PHLFigure 16. MAX481/MAX485/MAX490/MAX491/MAX1487Receiver t PLHPHL Figure 18. MAX483, MAX487–MAX489 Receiver t PLHLine Length vs. Data RateThe RS-485/RS-422 standard covers line lengths up to 4000 feet. For line lengths greater than 4000 feet, see Figure 23.Figures 19 and 20 show the system differential voltage for the parts driving 4000 feet of 26AWG twisted-pair wire at 110kHz into 120Ωloads.Typical ApplicationsThe MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 transceivers are designed for bidirectional data communications on multipoint bus transmission lines.Figures 21 and 22 show typical network applications circuits. These parts can also be used as line repeaters, with cable lengths longer than 4000 feet, as shown in Figure 23.To minimize reflections, the line should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possi-ble. The slew-rate-limited MAX483 and MAX487–MAX489are more tolerant of imperfect termination.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________13DIV Y -V ZRO5V 0V1V0V -1V5V 0V2µs/divFigure 19. MAX481/MAX485/MAX490/MAX491/MAX1487 System Differential Voltage at 110kHz Driving 4000ft of Cable Figure 20. MAX483, MAX487–MAX489 System Differential Voltage at 110kHz Driving 4000ft of CableFigure 21. MAX481/MAX483/MAX485/MAX487/MAX1487 Typical Half-Duplex RS-485 NetworkM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 14______________________________________________________________________________________Figure 22. MAX488–MAX491 Full-Duplex RS-485 NetworkFigure 23. Line Repeater for MAX488–MAX491Isolated RS-485For isolated RS-485 applications, see the MAX253 and MAX1480 data sheets.MAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________15_______________Ordering Information_________________Chip TopographiesMAX481/MAX483/MAX485/MAX487/MAX1487N.C. RO 0.054"(1.372mm)0.080"(2.032mm)DE DIGND B N.C.V CCARE * Contact factory for dice specifications.__Ordering Information (continued)M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 16______________________________________________________________________________________TRANSISTOR COUNT: 248SUBSTRATE CONNECTED TO GNDMAX488/MAX490B RO 0.054"(1.372mm)0.080"(2.032mm)N.C. DIGND Z A V CCYN.C._____________________________________________Chip Topographies (continued)MAX489/MAX491B RO 0.054"(1.372mm)0.080"(2.032mm)DE DIGND Z A V CCYREMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers______________________________________________________________________________________17Package Information(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to /packages .)S O I C N .E P SM A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487Low-Power, Slew-Rate-Limited RS-485/RS-422 Transceivers 18______________________________________________________________________________________Package Information (continued)(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to /packages .)MAX481/MAX483/MAX485/MAX487–MAX491Low-Power, Slew-Rate-Limited RS-485/RS-422 TransceiversMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________19©2003 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.M A X 481/M A X 483/M A X 485/M A X 487–M A X 491/M A X 1487P D I P N .E PSPackage Information (continued)(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to /packages .)。

MAX1400+5V , 18-Bit, Low-Power, Multichannel,Oversampling (Sigma-Delta) ADC________________________________________________________________Maxim Integrated Products119-1430; Rev 1; 7/02General DescriptionThe MAX1400 18-bit, low-power, multichannel, serial-output ADC uses a sigma-delta modulator with a digital decimation filter to achieve true 16-bit accuracy. The user-selectable decimation factor of the digital filter allows the conversion resolution to be reduced in exchange for a higher output data rate. The device achieves true 16-bit performance at an output data rate of up to 480sps. In addition, the modulator sampling frequency may be optimized for either lowest power dissipation or highest throughput rate. The MAX1400operates from +5V.This device offers three fully differential input channels that can be independently programmed with a gain between +1V/V and +128V/V. Furthermore, it can com-pensate an input-referred DC offset (such as system off-set) up to 117% of the selected full-scale range. These three differential channels may also be configured to operate as five pseudo-differential input channels. Two additional, fully differential system-calibration channels are provided for gain and offset error correction. External access is provided to the multiplexer (mux) output to facilitate additional signal processing.The MAX1400 can be configured to scan all signal inputs sequentially and provide the results through the serial interface with minimum communications overhead. When used with a 2.4576MH z or 1.024MH z master clock, the digital decimation filter can be programmed to produce zeros in its frequency response at the line fre-quency and associated harmonics, ensuring excellent line rejection without the need for further post-filtering.The MAX1400 comes in a 28-pin SSOP package.ApplicationsPortable Industrial Instruments Portable Weigh Scales Loop-Powered Systems Pressure TransducersFeatureso 18-Bit Resolution, Sigma-Delta ADC o 16-Bit Performance with No Missing Codes to 480sps o Low Quiescent Current250µA (operating mode)2µA (power-down mode)o 3 Fully Differential or 5 Pseudo-Differential Signal Input Channels o 2 Additional Fully Differential Calibration Channels/Auxiliary Input Channels o Access to the Mux Output/ADC Input o Programmable Gain and Offset o Fully Differential Reference Inputs o Converts Continuously or On Command o Automatic Channel Scanning and Continuous Data Output Mode o Operates with +5V Analog Supply and +3V or +5V Digital Supplyo SPI™/QSPI™-Compatible 3-Wire Serial Interface o 28-Pin SSOP PackageSPI and QSPI are trademarks of Motorola, Inc.Pin ConfigurationOrdering InformationFor pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .M A X 1400+5V , 18-Bit, Low-Power, Multichannel, Oversampling (Sigma-Delta) ADC 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICS(V+ = +5V ±5%, V DD = +2.7V to +5.25V, V REFIN+= +2.50V, REFIN- = AGND, f CLKIN = 2.4576MHz, T A = T MIN to T MAX , unless other-wise noted. Typical values are at T A = +25°C.)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.V+ to AGND, DGND.................................................-0.3V to +6V V DD to AGND, DGND...............................................-0.3V to +6V AGND to DGND.....................................................-0.3V to +0.3V Analog Inputs to AGND................................-0.3V to (V+ + 0.3V)Analog Outputs to AGND.............................-0.3V to (V+ + 0.3V)Reference Inputs to AGND...........................-0.3V to (V+ + 0.3V)CLKIN and CLKOUT to DGND...................-0.3V to (V DD + 0.3V)All Other Digital Inputs to DGND..............................-0.3V to +6V All Digital Outputs to DGND.......................-0.3V to (V DD + 0.3V)Maximum Current Input into Any Pin..................................50mA Continuous Power Dissipation (T A = +70°C)28-Pin SSOP (derate 9.52mW/°C above +70°C)........524mW Operating Temperature RangesMAX1400CAI .....................................................0°C to +70°C MAX1400EAI...................................................-40°C to +85°C Storage Temperature Range.............................-60°C to +150°C Lead Temperature (soldering, 10s).................................+300°CMAX1400+5V , 18-Bit, Low-Power, Multichannel,Oversampling (Sigma-Delta) ADC________________________________________________________________________________________3ELECTRICAL CHARACTERISTICS (continued)(V+ = +5V ±5%, V DD = +2.7V to +5.25V, V REFIN+= +2.50V, REFIN- = AGND, f CLKIN = 2.4576MHz, T A = T MIN to T MAX , unless other-wise noted. Typical values are at T A = +25°C.)M A X 1400+5V , 18-Bit, Low-Power, Multichannel, Oversampling (Sigma-Delta) ADC 4_______________________________________________________________________________________ELECTRICAL CHARACTERISTICS (continued)(V+ = +5V ±5%, V DD = +2.7V to +5.25V, V REFIN+= +2.50V, REFIN- = AGND, f CLKIN = 2.4576MHz, T A = T MIN to T MAX , unless other-wise noted. Typical values are at T = +25°C.)MAX1400+5V , 18-Bit, Low-Power, Multichannel,Oversampling (Sigma-Delta) ADC_______________________________________________________________________________________5ELECTRICAL CHARACTERISTICS (continued)(V+ = +5V ±5%, V DD = +2.7V to +5.25V, V REFIN+= +2.50V, REFIN- = AGND, f CLKIN = 2.4576MHz, T A = T MIN to T MAX , unless other-wise noted. Typical values are at T A = +25°C.)M A X 1400+5V , 18-Bit, Low-Power, Multichannel, Oversampling (Sigma-Delta) ADC 6_______________________________________________________________________________________Note 1:Nominal gain is 0.98. This ensures a full-scale input voltage may be applied to the part under all conditions without caus-ing saturation of the digital output data.Note 2:Positive Full-Scale Error includes zero-scale errors (unipolar offset error or bipolar zero error) and applies to both unipolarand bipolar input ranges. This error does not include the nominal gain of 0.98.Note 3:Full-Scale Drift includes zero-scale drift (unipolar offset drift or bipolar zero drift) and applies to both unipolar and bipolarinput ranges.Note 4:Gain Error does not include zero-scale errors. It is calculated as (full-scale error - unipolar offset error) for unipolar rangesand as (full-scale error - bipolar zero error) for bipolar ranges. This error does not include the nominal gain of 0.98.Note 5:Gain-Error Drift does not include unipolar offset drift or bipolar zero drift. It is effectively the drift of the part if zero-scaleerror is removed.Note 6:Use of the offset DAC does not imply that any input may be taken below AGND.Note 7:Additional noise added by the offset DAC is dependent on the filter cutoff, gain, and DAC setting. No noise is added for aDAC code of 0000.Note 8:Guaranteed by design or characterization; not production tested.Note 9:The input voltage must be within the Absolute Input Voltage Range specification.Note 10:All AIN and REFIN pins have identical input structures. Leakage is production tested only for the AIN3, AIN4, AIN5,CALGAIN, and CALOFF inputs.Note 11:The dynamic load presented by the MAX1400 analog inputs for each gain setting is discussed in detail in the SwitchingNetwork section .Values are provided for the maximum allowable external series resistance. Note that this value does not include any additional capacitance added by the user to the MUXOUT_ or ADCIN_ pins.Note 12:The input voltage range for the analog inputs is with respect to the voltage on the negative input of its respective differen-tial or pseudo-differential pair. Table 5 shows which inputs form differential pairs.Note 13:V REF = V REFIN+- V REFIN-.Note 14:These specifications apply to CLKOUT only when driving a single CMOS load.Note 15:The burn-out currents require a 500mV overhead between the analog input voltage and both V+ and AGND to operatecorrectly.ELECTRICAL CHARACTERISTICS (continued)(V+ = +5V ±5%, V DD = +2.7V to +5.25V, V REFIN+= +2.50V, REFIN- = AGND, f CLKIN = 2.4576MHz, T A = T MIN to T MAX , unless other-MAX1400+5V , 18-Bit, Low-Power, Multichannel,Oversampling (Sigma-Delta) ADC_______________________________________________________________________________________7Note 16:Measured at DC in the selected passband. PSR at 50Hz will exceed 120dB with filter notches of 25Hz or 50Hz and FASTbit = 0. PSR at 60Hz exceeds 120dB with filter notches of 20Hz or 60Hz and FAST bit = 0.Note 17:PSR depends on gain. For a gain of +1V/V, PSR is 70dB typical. For a gain of +2V/V, PSR is 75dB typical. For a gain of+4V/V, PSR is 80dB typical. For gains of +8V/V to +128V/V, PSR is 85dB typical.Note 18:Standby power-dissipation and current specifications are valid only with CLKIN driven by an external clock and with theexternal clock stopped. If the clock continues to run in standby mode, the power dissipation will be considerably higher.When used with a resonator or crystal between CLKIN and CLKOUT, the actual power dissipation and I DD in standby mode depends on the resonator or crystal type.TIMING CHARACTERISTICS(V+ = +5V ±5%, V DD = +2.7V to +5.25V, AGND = DGND, f CLKIN = 2.4576MHz; input logic 0 = 0V; logic 1 = V DD , T A = T MIN to T MAX ,unless otherwise noted.) (Notes 19, 20, 21)M A X 1400+5V , 18-Bit, Low-Power, Multichannel, Oversampling (Sigma-Delta) ADC 8_______________________________________________________________________________________TIMING CHARACTERISTICS (continued)(V+ = +5V ±5%, V DD = +2.7V to +5.25V, AGND = DGND, f CLKIN = 2.4576MHz; input logic 0 = 0V; logic 1 = V DD , T A = T MIN to T MAX ,unless otherwise noted.) (Notes 19, 20, 21)Note 19:All input signals are specified with t r = t f = 5ns (10% to 90% of V DD ).Note 20:See Figure 4.Note 21:Timings shown in tables are for the case where SCLK idles high between accesses. The part may also be used with theSCLK idling low between accesses, provided CS is toggled. In this case SCLK in the timing diagrams should be inverted and the terms “SCLK Falling Edge” and “SCLK Rising Edge” exchanged in the specification tables. If CS is permanently tied low, the part should only be operated with SCLK idling high between accesses.Note 22:CLKIN duty cycle range is 45% to 55%. CLKIN must be supplied whenever the MAX1400 is not in standby mode. If noclock is present, the device can draw higher current than specified.Note 23:The MAX1400 is production tested with f CLKIN at 2.5MHz (1MHz for some I DD tests).Note 24:Measured with the load circuit of Figure 1 and defined as the time required for the output to cross the V OL or V OH limits.Note 25:For read operations, SCLK active edge is falling edge of SCLK.Note 26:Derived from the time taken by the data output to change 0.5V when loaded with the circuit of Figure 1. The number is thenextrapolated back to remove effects of charging or discharging the 50pF capacitor. This ensures that the times quoted in the timing characteristics are true bus-relinquish times and are independent of external bus loading capacitances.Note 27:INT returns high after the first read after an output update. The same data can be read again while INT is high, but becareful not to allow subsequent reads to occur close to the next output update.Figure 1. Load Circuit for Bus Relinquish Time and V OL and V OH LevelsMAX1400+5V , 18-Bit, Low-Power, Multichannel,Oversampling (Sigma-Delta) ADC_______________________________________________________________________________________9Pin Description15AIN5Analog Input Channel 5. Used as a differential or pseudo-differential input with AIN6 (see the Communications Register section).NAME FUNCTION1CLKINClock Input. A crystal can be connected across CLKIN and CLKOUT. Alternatively, drive CLKIN with a CMOS-compatible clock at a nominal frequency of 2.4576MHz or 1.024MHz, and leave CLKOUT uncon-nected. Frequencies of 4.9152MHz and 2.048MHz can be used if the X2CLK control bit is set to 1.PIN 2CLKOUTClock Output. When deriving the master clock from a crystal, connect the crystal between CLKIN andCLKOUT. In this mode, the on-chip clock signal is not available at CLKOUT. Leave CLKOUT unconnected when CLKIN is driven with an external clock.3CSChip-Select Input. Active-low logic input used to enable the digital interface. With CS hard-wired low, the MAX1400 operates in its 3-wire interface mode with SCLK, DIN and DOUT used to interface to the device.CS is used either to select the device in systems with more than one device on the serial bus, or as a frame-synchronization signal for the MAX1400 when a continuous SCLK is used.4RESETActive Low Reset Input. Drive low to reset the control logic, interface logic, digital filter and analog modu-lator to power-on status. RESET must be high and CLKIN must be toggling in order to exit reset. 5MUXOUT+Positive Analog Mux Output. The positive differential output signal from the part’s internal input multiplex-er. Use this signal in conjunction with MUXOUT- and a high-quality external amplifier for additional signal processing before conversion. Return the processed output through ADCIN+ and ADCIN-. Connect MUXOUT+ directly to ADCIN+ if external processing is not required.6MUXOUT-Negative Analog Mux Output. The negative differential output signal from the part’s internal input multi-plexer. Use this signal in conjunction with MUXOUT+ and a high-quality external amplifier for additional signal processing before conversion. Return the processed output through ADCIN+ and ADCIN-.Connect MUXOUT- directly to ADCIN- if external processing is not required.7ADCIN+Positive Analog Input. A direct input to the positive buffer and the positive differential input terminal of the ADC, bypassing the input mux. This signal forms a differential input pair with ADCIN-. Connect ADCIN+ to MUXOUT+ when direct access is not required.8ADCIN-Negative Analog Input. A direct input to the negative buffer and the negative differential input terminal of the ADC - bypassing the input mux. This signal forms a differential input pair with ADCIN+. Connect ADCIN- to MUXOUT- when direct access is not required.9AGND Analog Ground. Reference point for the analog circuitry. AGND connects to the IC substrate.10V+Analog Positive Supply Voltage (+4.75V to +5.25V)11AIN1Analog Input Channel 1. Can be used as a pseudo-differential input with AIN6 as common, or as the posi-tive input of the AIN1/AIN2 differential analog input pair (see the Communications Register section).12AIN2Analog Input Channel 2. Can be used as a pseudo-differential input with AIN6 as common, or as the neg-ative input of the AIN1/AIN2 differential analog input pair (see the Communications Register section).13AIN3Analog Input Channel 3. Can be used as a pseudo-differential input with AIN6 as common, or as the posi-tive input of the AIN3/AIN4 differential analog input pair (see the Communications Register section).14AIN4Analog Input Channel 4. Can be used as a pseudo-differential input with AIN6 as common, or as the neg-ative input of the AIN3/AIN4 differential analog input pair (see the Communications Register section).16AIN6Analog Input 6. Can be used as a common point for AIN1 through AIN5 in pseudo-differential mode, or as the negative input of the AIN5/AIN6 differential analog input pair (see the Communications Register section).M A X 1400+5V , 18-Bit, Low-Power, Multichannel, Oversampling (Sigma-Delta) ADC 10______________________________________________________________________________________Pin Description (continued)分销商库存信息:MAXIMMAX1400EAI+MAX1400CAI+T MAX1400EAI+T MAX1400CAI+。

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Typical values are at T A = +25°C.) (Note 1)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.V DD to GND..............................................................-0.3V to +6V All Other Pins to GND.................................-0.3V to (V DD + 0.3V)Output Short-Circuit Duration.....................................Continuous Continuous Current (MICOUT, MICBIAS).......................±100mA All Other Pins....................................................................±20mAContinuous Power Dissipation (T A = +70°C)14-Pin TDFN-EP(derate 16.7mW/°C above +70°C)........................1481.5mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature......................................................+150°C Lead Temperature (soldering, 10s).................................+300°C Bump Temperature (soldering) Reflow............................+235°CNBY:925௥ᎌBHDਜ਼ࢅᐅဉ൱యज़ມᒙ࢟വࡼ൱యज़हࡍ໭_______________________________________________________________________________________3Note 1:Devices are production tested at T A = +25°C. Limits over temperature are guaranteed by design.Note 2:Dynamic range is calculated using the EIAJ method. The input is applied at -60dBFS (0.707μV RMS ), f IN = 1kHz.Note 3:Attack time measured as time from AGC trigger to gain reaching 90% of its final value.Note 4:CG is connected to an external DC voltage source, and adjusted until V MICOUT = 1.23V.Note 5:CG connected to GND with 2.2μF.ELECTRICAL CHARACTERISTICS (continued)(V DD = 3.3V, SHDN = V DD , C CT = 470nF, C CG = 2μF, GAIN = V DD , T A = T MIN to T MAX , unless otherwise specified. Typical values are at T = +25°C.) (Note 1)N B Y :925௥ᎌBHDਜ਼ࢅᐅဉ൱యज़ມᒙ࢟വࡼ൱యज़हࡍ໭4_______________________________________________________________________________________```````````````````````````````````````````````````````````````````````࢜ቯ৔ᔫᄂቶ(V DD = 5V, C CT = 470nF, C CG = 2.2μF, V TH = V MICBIAS x 0.4, GAIN = V DD (40dB), AGC disabled, no load, R L = 10k Ω, C OUT = 1μF,T A = +25°C, unless otherwise noted.)GAIN vs. FREQUENCYFREQUENCY (Hz)G A I N (d B )10k1k 1001020304050607080010100kPOWER-SUPPLY REJECTION RATIOvs. FREQUENCYFREQUENCY (Hz)P S R R (d B )10k1k 100-70-60-50-40-30-20-100-8010100kMICBIAS POWER-SUPPLY REJECTION RATIOvs. FREQUENCYFREQUENCY (Hz)P S R R (d B )10k1k 100-100-90-80-70-60-50-40-30-11010100kSUPPLY CURRENT vs. SUPPLY VOLTAGEM A X 9814 t o c 04SUPPLY VOLTAGE (V)S U P P L Y C U R R E N T (m A )5.55.04.04.53.53.02.62.72.82.93.03.13.23.33.43.52.52.56.0SHUTDOWN CURRENT vs. SUPPLY VOLTAGEM A X 9814 t o c 05SUPPLY VOLTAGE (V)S H U T D O W N C U R R E N T (n A )5.55.04.54.03.53.00.10.20.30.40.502.56.0MICROPHONE BIAS VOLTAGEvs. MICROPHONE BIAS SOURCE CURRENTM A X 9814 t o c 06I MICBIAS (mA)V M I C B I A S V O L T A G E (V )2520151050.51.01.52.02.50030TOTAL HARMONIC DISTORTION PLUS NOISEvs. FREQUENCYFREQUENCY (Hz)T H D +N (%)10k1k 1000.11100.0110100kTOTAL HARMONIC DISTORTION PLUS NOISEvs. OUTPUT VOLTAGEOUTPUT VOLTAGE (V RMS )T H D +N (%)1.00.50.11100.011.5INPUT-REFERRED NOISEvs. FREQUENCYFREQUENCY (kHz)I N P U T -R E F E R R E D N O I S E (μV R M S /√H z )1010.1100100.0110010001NBY:925௥ᎌBHDਜ਼ࢅᐅဉ൱యज़ມᒙ࢟വࡼ൱యज़हࡍ໭_______________________________________________________________________________________5MICBIAS NOISE vs. FREQUENCYMA X 9814 t o c 10FREQUENCY (Hz)M I C B I A S N O I S E(n V RM S /√H z )10k1k 100100100010,0001010100kSMALL-SIGNAL PULSE RESPONSE200μs/divV MICIN 10mV/div0VV MICOUT500mV/div0VTURN-ON RESPONSEM A X 9814 t o c 1220ms/divV SHDN 5V/div 0V V MICBIAS 2V/div 0VV MICOUT 1V/div 0VV OUT vs. V INV IN (mV RMS )V O U T (V R M S)100500.250.500.751.0000150V OUT vs. V INV IN (mV RMS )V O U T (V R M S)3020100.250.500.751.000040V OUT vs. V INV IN (mV RMS )V O U T (V R M S )1050.250.500.751.000015ATTACK TIME200μs/divV MICOUT 500mV/divC CT = 47nF0VATTACK TIME200μs/divV MICOUT 500mV/div0VHOLD AND RELEASE TIME20ms/divV MICOUT 500mV/divC CT = 47nF A/R = GND0V``````````````````````````````````````````````````````````````````````࢜ቯ৔ᔫᄂቶ)ኚ*(V DD = 5V, C CT = 470nF, C CG = 2.2μF, V TH = V MICBIAS x 0.4, GAIN = V DD (40dB), AGC disabled, no load, R L = 10k Ω, C OUT = 1μF,T A = +25°C, unless otherwise noted.)N B Y :925௥ᎌBHDਜ਼ࢅᐅဉ൱యज़ມᒙ࢟വࡼ൱యज़हࡍ໭6_______________________________________________________________________________________HOLD AND RELEASE TIME40ms/divV MICOUT 500mV/div0VHOLD AND RELEASE TIME100ms/divV MICOUT 500mV/div0V```````````````````````````````````````````````````````````````````````````````፛୭ႁී``````````````````````````````````````````````````````````````````````࢜ቯ৔ᔫᄂቶ)ኚ*(V DD = 5V, C CT = 470nF, C CG = 2.2μF, V TH = V MICBIAS x 0.4, GAIN = V DD (40dB), AGC disabled, no load, R L = 10k Ω, C OUT = 1μF,T A = +25°C, unless otherwise noted.)NBY:925௥ᎌBHDਜ਼ࢅᐅဉ൱యज़ມᒙ࢟വࡼ൱యज़हࡍ໭_______________________________________________________________________________________7MAX9814 AGC DISABLED400μs/div V MICIN 100mV/divV MICOUT(AC-COUPLED)1V/divMAX9814 fig01aMAX9814 AGC ENABLED400μs/divV MICIN 100mV/divV MICOUT(AC-COUPLED)1V/divMAX9814 fig01b0V0V0V0V```````````````````````````````ሮᇼႁීNBY:925ဵጙ౒ࢅ߅۾Ă঱ອᒠ൱యज़हࡍ໭Ljดᒙᔈࣅᐐፄ఼ᒜ)BHD*ጲૺࢅᐅဉ൱యज़ມᒙăNBY:925ဵᎅࢅᐅဉ༄ᒙहࡍ໭Ăభܤᐐፄहࡍ໭)WHB*Ăၒ߲हࡍ໭Ă൱యज़ມᒙखည໭ጲૺBHD఼ᒜ࢟വࢀࣶৈݙᄴ࢟വᔝ߅ăดݝ൱యज़ມᒙखည໭ᄋ৙3WࡼມኹLjး፿᎖ࡍࣶၫᓘ૵ᄏ࢟ྏါ൱యज़ăNBY:925ॊᆐྯ଀Lj࣪ၒྜྷ஠ቲहࡍăᏴ࢒ጙ଀Ljၒྜྷᄰਭᐐፄᆐ23eCࡼࢅᐅဉ༄ᒙहࡍ໭஠ቲદߡਜ਼हࡍǗ࢒औ଀ᐌᎅBHD఼ᒜࡼWHBᔝ߅LjWHB0BHDᔝ੝ถ৫ဧᐐፄᏴ31eCᎧ1eCᒄମܤછǗၒ߲हࡍ໭ဵᔢઁጙ଀Lj௥ᎌ9eCĂ29eCĂ31eCྯৈݙᄴࡼৼࢾᐐፄLjభᄰਭጙৈྯზ൝૷ၒྜྷܠ߈࿸ᒙăBHDᇄኹჁဟLjNBY:925ถ৫ᄋ৙51eCĂ61eC૞71eCࡼᐐፄăᔈࣅᐐፄ఼ᒜ)BHD*ݙ௥۸BHDࡼ໭ୈᏴၒྜྷᐐፄਭࡍဟLjၒ߲୓્߲ሚሻ݆ǗऎᏴၒྜྷᐐፄਭࡍဟLjBHDถ৫ܜ඾ၒ߲ሻ݆ăᅄ2Ⴥာᆐᐐፄਭࡍࡼ൱యज़ၒྜྷᏴ௥ᎌBHDਜ਼ݙࡒBHDࡼ༽ౚሆࡼ܈୷ăNBY:925ࡼBHD࣪ᐐፄ஠ቲ఼ᒜLj၅ሌଶހၒ߲࢟ኹဵ॥ިਭᎾ࿸ඡሢăႲઁLjᄰਭభኡࡼဟମޟၫଢ଼ࢅ൱యज़हࡍ໭ᐐፄLjጲኀᑵਭࡍࡼၒ߲࢟ኹ७ᒋăᑚጙਭ߈߂ᆐ໪ࣅဟମăࡩၒ߲ቧ੓७ᒋଢ଼ࢅઁLjᐐፄᏴ੪࣢ဟମดۣߒၱିᓨზLjႲઁၒ߲ቧ੓દൻᐐଝࡵᑵޟᒋăকਭ߈߂ᆐۣߒਜ਼ျहဟମăहࡍ໭ࢯஂၒྜྷቧ੓ࡼႥࣞᎅᅪݝࢾဟ࢟ྏD DU ਜ਼B0S࣡࢟ኹ࿸ᒙăBHDඡሢభᄰਭW UI ࢯஂăᐐፄၱି೟ᆐၒྜྷቧ੓७ᒋࡼ਽ၫLjᔢࡍBHDၱିᆐ31eCăᅄ3৊߲೫ၒྜྷᅃ཭ި߲Ꮎ࿸ඡሢဟLj࣪ၒ߲໪ࣅဟମĂۣߒဟମਜ਼ျहဟମࡼ፬ሰăྙਫ๼ᒙࡼ໪ࣅဟମਜ਼ျहဟମሰ።ვ౐LjᐐፄႲቧ੓ࣅზܤછऎ౐ႥࢯஂLjޟޟ્ޘညಢ႒Đກ཭đဉ)qvnqjoh*૞Đࠇᇦđဉ)csfbuijoh*ࡼፒຫᐅဉăࢯஂBHDࡼဟମޟၫဧ໚ᎧဉᏎປ๼Lj࠭ऎࡉࡵᔢଛ቉ਫă࣪᎖กቋጲDEፒಘᆐᓍገፒᏎࡼ።፿౶ႁLjᅎୀ໪ࣅဟମᆐ271μtLjျहဟମᆐ91ntăᄰޟ༽ౚሆLjፒಘ݃ह࿸۸ገ܈Ꭻፒ૞࢟፬ࢀ࿸۸ኊገৎ࣢ࡼျहဟମăᅄ2/!ࡒᎌBHDਜ਼඗ᎌBHDࡼ൱యज़ၒྜྷ໪ࣅဟମ໪ࣅဟମဵᒎࡩၒྜྷቧ੓ިਭඡሢ࢟ຳઁLjBHDଢ଼ࢅᐐፄჅኊࡼဟମăᐐፄᏴ໪ࣅဟମดጲᒎၫተါၱିLjࢾፃᆐጙৈဟମޟၫăকဟମޟၫᆐ3511y D DU ෇)໚ᒦD DU ဵᅪݝࢾဟ࢟ྏ*ǖ•ኡན୷࣢ࡼ໪ࣅဟମLjጲۣᑺBHD౐Ⴅሰ።ၾზቧ੓Ljಿྙૣ৴ဉ)ፒಘ*૞།ૣဉ)EWE*ă•ኡ፿୷ޠࡼ໪ࣅဟମLjBHD୓઄൒ၾဟख़ᒋLjᒑᎌࡩဉሰීመᐐଝဟݣଢ଼ࢅᐐፄăၾဟख़ᒋ݀ݙۻၱିLjࡣ୷ሰࡼဉፒ୓ۻၱିăᑚዹభ࠭ፒ೟࿟ଢ଼ࢅሰဉLjဧࣅზपᆍᔢࡍછăۣߒဟମۣߒဟମဵᒎቧ੓ଢ଼ࡵඡሢጲሆĂျहਭ߈ఎဪጲ༄ࡼዓߕăۣߒဟମดݝ࿸ᒙᆐ41ntLj݀༦ݙభࢯăࡩቧ੓ިਭඡሢLjᒮቤ஠ྜྷ໪ࣅ୿ࣤဟLjۣߒဟମᒫᒏăျहဟମျहဟମဵᒎቧ੓ࢰൢᒗඡሢጲሆLj݀༦ளਭ41ntࡼۣߒဟମᒄઁLjᐐፄૄࡵ໚ᑵޟၺຳჅኊࡼဟମăျहဟମࢾፃᆐࡩၒྜྷቧ੓ࢰൢᒗUIඡሢጲሆLj݀༦ளਭ41nt ࡼۣߒဟମᒄઁLjᐐፄ࠭31eCኹჁျहࡵᑵޟᐐፄࡼ21&ࡼဟମăျहဟମభࢯLj໚ᔢቃᒋᆐ36ntăျहဟମᎅD DU ࿸ᒙࡼ໪ࣅဟମጲૺಽ፿B0S )ྙܭ2Ⴥာ*࿸ᒙࡼ໪ࣅ0ျहဟମ܈ཀྵࢾǖ•ݧ፿ቃ܈ᒋLjဧBHDࡼႥࣞࡉࡵᔢࡍă•ݧ፿ࡍ܈ᒋLjဧፒᒠࡉࡵᔢଛLjऴᒏBHDᒮআࢯஂ࣢ဟମดި߲ඡሢࡼቧ੓ăBHDၒ߲ඡሢ૮૚BHD৔ᔫࡼၒ߲ඡሢభᄰਭᅪݝ࢟ᔜॊኹ໭ࢯஂăᅲ߅࣪ॊኹ໭ࡼ࿸ᒙઁLjBHD୓ଢ଼ࢅᐐፄLjဧၒ߲࢟ኹᎧUIၒྜྷ࣡࿸ᒙࡼ࢟ኹሤປ๼ă൱యज़ມᒙNBY:925ᎅดݝᄋ৙ࢅᐅဉ൱యज़ມᒙ࢟ኹLjభདࣅࡍࣶၫᓘ૵ᄏ࢟ྏါ൱యज़ăࢯஂ൱యज़ມᒙᒗ3WLjጲۣᑺ஠ྜྷࢅᐅဉ༄ᒙहࡍ໭ࡼၒྜྷቧ੓ݙۻὥᆡࡵ࢐ă```````````````````````````````።፿ቧᇦ࿸ᒙ໪ࣅဟମਜ਼ျहဟମ໪ࣅဟମਜ਼ျहဟମॊܰᎅDUਜ਼HOEᒄମࡼ࢟ྏጲૺB0Sࡼ൝૷ᓨზ)ܭ2*௼ࢾăB0Sᆐྯზ൝૷ၒྜྷLjభ࿸ᒙ໪ࣅᎧျहဟମ܈ăো௣ܭ3Ⴥ೰ࡼሤ።࢟ྏLjభጲኡᐋ໪ࣅဟମਜ਼ျहဟମăN B Y :925௥ᎌBHDਜ਼ࢅᐅဉ൱యज़ມᒙ࢟വࡼ൱యज़हࡍ໭8_______________________________________________________________________________________10ms/divATTACKRELEASEHOLDᅄ3/!ၒྜྷᅃ཭ިਭBHDඡሢܭ2/!໪ࣅᎧျह܈ܭ3/!໪ࣅ.ျहဟମ࿸ᒙBHDඡሢྦገ࿸ᒙ൱యज़ၒ߲ὥᆡဟࡼၒ߲࢟ኹඡሢLj።ᏴNJDCJBTਜ਼࢐ᒄମೌ୻ᅪݝ࢟ᔜॊኹ໭Lj࢟ᔜॊኹ໭ၒ߲ೌ୻ࡵUIă࢟ኹW UIభཀྵࢾၒ߲ὥᆡဟࡼख़ᒋ࢟ኹඡሢăࠥဟLjၒ߲࣡ࡼᔢࡍቧ੓ڼ७ᆐW UIࡼ3۶Ljۣ݀ߒݙܤLjᒇࡵၒྜྷቧ੓७ᒋၱିᆐᒏăྦገணᒏBHDLjభ୓UIೌ୻ᒗNJDCJBTă൱యज़ມᒙ࢟ᔜNJDCJBTభᏎ߲31nBࡼ࢟ഗăኡᐋးࡩࡼS NJDCJBTLj࠭ऎᆐᓘ૵ᄏ൱యज़ᄋ৙Ⴥኊገࡼມᒙ࢟ഗăጙۅ౶ႁLj3/3lΩࡼᔜᒋ࣪᎖࢜ቯഉැࣞࡼ൱యज़ጯளᔗ৫೫ăਈ᎖ມᒙ࢟ᔜࡼኡᐋLj༿ݬఠ൱యज़ၫ௣ᓾ೯ăມᒙ࢟ྏNBY:925ࡼCJBTၒ߲ᏴดݝளਭદߡLjᄋ৙ࢅᐅဉມኹăݧ፿ጙᒑ581oGࡼ࢟ྏ୓CJBT๬വᒗ࢐ăၒྜྷ࢟ྏ൱యज़हࡍ໭ࡼၒྜྷୣഗẮ੝࢟ྏ)D JO*ਜ਼ၒྜྷᔜఝ)S JO*ᔝ߅೫ጙৈ঱ᄰ൉݆໭Ljభ൉߹ၒྜྷቧ੓ᒦࡼჅᎌᒇഗມᒙ)ݬ୅࢜ቯ።፿࢟വ0৖ถౖᅄ*ăD 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BiCMOS`````````````````````````````````፛୭๼ᒙN B Y :925൱యज़हࡍ໭12______________________________________________________________________________________`````````````````````````````````````````````````````````````````````````````ॖᓤቧᇦྙኊᔢதࡼॖᓤᅪተቧᇦਜ਼੆๤ݚ௜Lj༿އኯ/packages ăNBY:925൱యज़हࡍ໭______________________________________________________________________________________13````````````````````````````````````````````````````````````````````````````````ॖᓤቧᇦ)ኚ*ྙኊᔢதࡼॖᓤᅪተቧᇦਜ਼੆๤ݚ௜Lj༿އኯ/packages ăN B Y :925൱యज़हࡍ໭````````````````````````````````````````````````````````````````````````````ኀࢿ಼ဥNbyjnݙ࣪Nbyjnޘອጲᅪࡼྀੜ࢟വဧ፿ঌᐊLjጐݙᄋ৙໚ᓜಽ኏భăNbyjnۣഔᏴྀੜဟମĂ඗ᎌྀੜᄰۨࡼ༄ᄋሆኀখޘອᓾ೯ਜ਼ਖৃࡼཚಽă14____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2009 Maxim Integrated ProductsNbyjn ဵNbyjn!Joufhsbufe!Qspevdut-!Jod/ࡼᓖݿ࿜ܪăNbyjn ۱யێူࠀ۱ய9439ቧረᎆᑶܠ൩211194඾ॅ࢟જǖ911!921!1421࢟જǖ121.732262::ࠅᑞǖ121.732263::。

精心整理MAX912/MAX913————单/双路，超高速，低功耗，精密的TTL比较器1.总体描述MAX913（单）和MAX912（双）高速，低功耗比较器是一个拥有独特设计就是在其线性区域是它的比较是可以防止振荡。

没有要求最低输入转换率。

它是由差分输入和互补的TTL输出。

快电流使V/F转该2.3.特点单无电源电流扣球稳定的线性区可投入任一电源低失调电压：0.8mV4.引脚配置顶视图：5.绝对最大额定值：正电源电压 (7V)负电源电压..............................................-7V差分输入电压.......................................±15V输入电压....................................-0.3V至15V锁存引脚电压...................................等于耗材连续输出电流.....................................±20mA连续功耗（TA=70℃）8引脚塑料DIP（减少9.09mW/妹高于70°）......727mW8引脚SO（减少5.88mW/每高于70°).................471mW8引脚CERDIP（减少8.00mW/每高于70°).........640mW16引脚塑料DIP（减少10.53mW/高于70°）.......842mW16引脚窄的SO（减免8.70mW/高于70°）..........696mW16引脚CERDIP（减免10.00mW/高于70°)..........800mW6.（℃）注1IOS）注2的tPD=+-的注3注47.传输延迟与负载电容：8.引脚说明：MAX912引脚名称功能1V+正电源。

3D max中英文对照表一、File〈文件〉New〈新建〉Reset〈重置〉Open〈打开〉Save〈保存〉Save As〈保存为〉Save selected〈保存选择〉XRef Objects〈外部引用物体〉XRef Scenes〈外部引用场景〉Merge〈合并〉Merge Animation〈合并动画动作〉Replace〈替换〉Import〈输入〉Export〈输出〉Export Selected〈选择输出〉Archive〈存档〉Summary Info〈摘要信息〉File Properties〈文件属性〉View Image File〈显示图像文件〉History〈历史〉Exit〈退出〉二、Edit〈菜单〉Undo or Redo〈取消/重做〉Hold and fetch〈保留/引用〉Delete〈删除〉Clone〈克隆〉Select All〈全部选择〉Select None〈空出选择〉Select Invert〈反向选择〉Select By〈参考选择〉Color〈颜色选择〉Name〈名字选择〉Rectangular Region〈矩形选择〉Circular Region〈圆形选择〉Fabce Region〈连点选择〉Lasso Region〈套索选择〉Region:〈区域选择〉Window〈包含〉Crossing〈相交〉Named Selection Sets〈命名选择集〉Object Properties〈物体属性〉三、Tools〈工具〉Transform Type-In〈键盘输入变换〉Display Floater〈视窗显示浮动对话框〉Selection Floater〈选择器浮动对话框〉Light Lister〈灯光列表〉Mirror〈镜像物体〉Array〈阵列〉Align〈对齐〉Snapshot〈快照〉Spacing Tool〈间距分布工具〉Normal Align〈法线对齐〉Align Camera〈相机对齐〉Align to View〈视窗对齐〉Place Highlight〈放置高光〉Isolate Selection〈隔离选择〉Rename Objects〈物体更名〉四、Group〈群组〉Group〈群组〉Ungroup〈撤消群组〉Open〈开放组〉Close〈关闭组〉Attach〈配属〉Detach〈分离〉Explode〈分散组〉五、Views〈查看〉Undo View Change/Redo View change〈取消/重做视窗变化〉Save Active View/Restore Active View〈保存/还原当前视窗〉Viewport Configuration〈视窗配置〉Grids〈栅格〉Show Home Grid〈显示栅格命令〉Activate Home Grid〈活跃原始栅格命令〉Activate Grid Object〈活跃栅格物体命令〉Activate Grid to View〈栅格及视窗对齐命令〉Viewport Background〈视窗背景〉Update Background Image〈更新背景〉Reset Background Transform〈重置背景变换〉Show Transform Gizmo〈显示变换坐标系〉Show Ghosting〈显示重橡〉Show Key Times〈显示时间键〉Shade Selected〈选择亮显〉Show Dependencies〈显示关联物体〉Match Camera to View〈相机与视窗匹配〉Add Default Lights To Scene〈增加场景缺省灯光〉Redraw All Views〈重画所有视窗〉Activate All Maps〈显示所有贴图〉Deactivate All Maps〈关闭显示所有贴图〉Update During Spinner Drag〈微调时实时显示〉Adaptive Degradation Toggle〈绑定适应消隐〉Expert Mode〈专家模式〉六、Create〈创建〉Standard Primitives〈标准图元〉Box〈立方体〉Cone〈圆锥体〉Sphere〈球体〉GeoSphere〈三角面片球体〉Cylinder〈圆柱体〉Tube〈管状体〉Torus〈圆环体〉Pyramid〈角锥体〉Plane〈平面〉Teapot〈茶壶〉Extended Primitives〈扩展图元〉Hedra〈多面体〉Torus Knot〈环面纽结体〉Chamfer Box〈斜切立方体〉Chamfer Cylinder〈斜切圆柱体〉Oil Tank〈桶状体〉Capsule〈角囊体〉Spindle〈纺锤体〉L-Extrusion〈L形体按钮〉Gengon〈导角棱柱〉C-Extrusion〈C形体按钮〉RingWave〈环状波〉Hose〈软管体〉Prism〈三棱柱〉Shapes〈形状〉Line〈线条〉Text〈文字〉Arc〈弧〉Circle〈圆〉Donut〈圆环〉Ellipse〈椭圆〉Helix〈螺旋线〉NGon〈多边形〉Rectangle〈矩形〉Section〈截面〉Star〈星型〉Lights〈灯光〉Target Spotlight〈目标聚光灯〉Free Spotlight〈自由聚光灯〉Target Directional Light〈目标平行光〉Directional Light〈平行光〉Omni Light〈泛光灯〉Skylight〈天光〉Target Point Light〈目标指向点光源〉Free Point Light〈自由点光源〉Target Area Light〈指向面光源〉IES Sky〈IES天光〉IES Sun〈IES阳光〉SuNLIGHT System and Daylight〈太阳光及日光系统〉Camera〈相机〉Free Camera〈自由相机〉Target Camera〈目标相机〉Particles〈粒子系统〉Blizzard〈暴风雪系统〉PArray〈粒子阵列系统〉PCloud〈粒子云系统〉Snow〈雪花系统〉Spray〈喷溅系统〉Super Spray〈超级喷射系统〉七、Modifiers〈修改器〉Selection Modifiers〈选择修改器〉Mesh Select〈网格选择修改器〉Poly Select〈多边形选择修改器〉Patch Select〈面片选择修改器〉Spline Select〈样条选择修改器〉V olume Select〈体积选择修改器〉FFD Select〈自由变形选择修改器〉NURBS Surface Select〈NURBS表面选择修改器〉Patch/Spline Editing〈面片/样条线修改器〉：Edit Patch〈面片修改器〉Edit Spline〈样条线修改器〉Cross Section〈截面相交修改器〉Surface〈表面生成修改器〉Delete Patch〈删除面片修改器〉Delete Spline〈删除样条线修改器〉Lathe〈车床修改器〉Normalize Spline〈规格化样条线修改器〉Fillet/Chamfer〈圆切及斜切修改器〉Trim/Extend〈修剪及延伸修改器〉Mesh Editing〈表面编辑〉Cap Holes〈顶端洞口编辑器〉Delete Mesh〈编辑网格物体编辑器〉Edit Normals〈编辑法线编辑器〉Extrude〈挤压编辑器〉Face Extrude〈面拉伸编辑器〉Normal〈法线编辑器〉Optimize〈优化编辑器〉Smooth〈平滑编辑器〉STL Check〈STL检查编辑器〉Symmetry〈对称编辑器〉Tessellate〈镶嵌编辑器〉Vertex Paint〈顶点着色编辑器〉Vertex Weld〈顶点焊接编辑器〉Animation Modifiers〈动画编辑器〉Skin〈皮肤编辑器〉Morpher〈变体编辑器〉Flex〈伸缩编辑器〉Melt〈熔化编辑器〉Linked XForm〈连结参考变换编辑器〉Patch Deform〈面片变形编辑器〉Path Deform〈路径变形编辑器〉Surf Deform〈表面变形编辑器〉Surf Deform〈空间变形编辑器〉UV Coordinates〈贴图轴坐标系〉UVW Map〈UVW贴图编辑器〉UVW Xform〈UVW贴图参考变换编辑器〉Unwrap UVW〈展开贴图编辑器〉Camera Map〈相机贴图编辑器〉Camera Map〈环境相机贴图编辑器〉Cache Tools〈捕捉工具〉Point Cache〈点捕捉编辑器〉Subdivision Surfaces〈表面细分〉MeshSmooth〈表面平滑编辑器〉HSDS Modifier〈分级细分编辑器〉Free Form Deformers〈自由变形工具〉FFD 2×2×2/FFD 3×3×3/FFD 4×4×4〈自由变形工具2×2×2/3×3×3/4×4×4〉FFD Box/FFD Cylinder〈盒体和圆柱体自由变形工具〉Parametric Deformers〈参数变形工具〉Bend〈弯曲〉Taper〈锥形化〉Twist〈扭曲〉Noise〈噪声〉Stretch〈缩放〉Squeeze〈压榨〉Push〈推挤〉Relax〈松弛〉Ripple〈波纹〉Wave〈波浪〉Skew〈倾斜〉Slice〈切片〉Spherify〈球形扭曲〉Affect Region〈面域影响〉Lattice〈栅格〉Mirror〈镜像〉Displace〈置换〉XForm〈参考变换〉Preserve〈保持〉Surface〈表面编辑〉Material〈材质变换〉Material By Element〈元素材质变换〉Disp Approx〈近似表面替换〉NURBS Editing〈NURBS面编辑〉NURBS Surface Select〈NURBS表面选择〉Surf Deform〈表面变形编辑器〉Disp Approx〈近似表面替换〉Radiosity Modifiers〈光能传递修改器〉Subdivide〈细分〉Subdivide〈超级细分〉八、Character〈角色人物〉Create Character〈创建角色〉Destroy Character〈删除角色〉Lock/Unlock〈锁住与解锁〉Insert Character〈插入角色〉Save Character〈保存角色〉Bone Tools〈骨骼工具〉Set Skin Pose〈调整皮肤姿势〉Assume Skin Pose〈还原姿势〉Skin Pose Mode〈表面姿势模式〉九、Animation〈动画〉IK Solvers〈反向动力学〉HI Solver〈非历史性控制器〉HD Solver〈历史性控制器〉IK Limb Solver〈反向动力学肢体控制器〉SplineIK Solver〈样条反向动力控制器〉Constraints〈约束〉Attachment Constraint〈附件约束〉Surface Constraint〈表面约束〉Path Constraint〈路径约束〉Position Constraint〈位置约束〉Link Constraint〈连结约束〉LookAt Constraint〈视觉跟随约束〉Orientation Constraint〈方位约束〉Transform Constraint〈变换控制〉Link Constraint〈连接约束〉Position/Rotation/Scale〈PRS控制器〉Transform Script〈变换控制脚本〉Position Controllers〈位置控制器〉Audio〈音频控制器〉Bezier〈贝塞尔曲线控制器〉Expression〈表达式控制器〉Linear〈线性控制器〉Motion Capture〈动作捕捉〉Noise〈燥波控制器〉Quatermion(TC〈TCB控制器〉Reactor〈反应器〉Spring〈弹力控制器〉Script〈脚本控制器〉XYZ〈XYZ位置控制器〉Attachment Constraint〈附件约束〉Path Constraint〈路径约束〉Position Constraint〈位置约束〉Surface Constraint〈表面约束〉Rotation Controllers〈旋转控制器〉注：该命令工十一个子菜单。

General DescriptionThe MAX1894/MAX1924 are lithium-ion/lithium-polymer (Li+) battery-pack protector ICs for 3- or 4-series Li+ bat-tery packs. The MAX1894/MAX1924 enhance the useful operating life of Li+ batteries by monitoring individual cell voltages and preventing over/undervoltage conditions.The MAX1894/MAX1924 also protect the battery pack against charge current, discharge current, and pack-short fault conditions.In case of a fault condition, on-board drivers control external P-channel MOSFETs, which disconnect the cells from the pack external terminals. The external protection MOSFETs are connected in a common-source configura-tion that does not require external pullup resistors. The MAX1894/MAX1924 use only one current-sense resistor to achieve the protection features. All protection thresh-olds and delays do not require any external components and are trimmed at the factory.If any cell voltage drops below the undervoltage thresh-old, the MAX1894/MAX1924 disconnect the pack from the load and power down to prevent deep discharge of the pack. The MAX1894/MAX1924 offer a trickle-charge feature, which provides a low-current path to safely charge a deeply discharged pack. The MAX1894/MAX1924 also have two logic-level inputs, which can be used by a microcontroller to disable the protection MOSFETs and to put the device in shutdown. The MAX1894/MAX1924 have low quiescent current (30µA typ) and ultra-low shutdown current (0.8µA typ) to pre-vent deep-cell discharge.The MAX1894X is designed for 4-series battery packs,without hysteresis on the protection thresholds. The MAX1924V and MAX1924X include hysteresis for the 3-and 4-series packs, respectively.Applications3- or 4-Series Li+ Battery PacksFeatureso Protect Against Cell OvervoltageFactory Programmable Limits from 4V to 4.4V Accurate to ±0.5% o Protect Against Cell UndervoltageFactory Programmable Limits from 2V to 3.2V Accurate to ±2.0%o Protect Against Charge, Discharge, and Pack-Short Current Faults o Automatically Trickle Charges Deeply Discharged Cells o Fully Integrated MOSFET Drivers Do Not Require Pullup Resistors o 0.8µA (typ) Shutdown Supply Current Prevents Deep Discharge of Cells o 30µA (typ) Operating Supply Current o 28V (max) Input Voltageo Available in Small 16-Pin QSOP PackageMAX1894/MAX1924Advanced Li+ Battery-Pack Protectors________________________________________________________________Maxim Integrated Products1Pin Configuration19-2278; Rev 0; 4/02For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering Information*Contact factory for alternative threshold voltages.Typical Applications Circuits appear at end of data sheet.M A X 1894/M A X 1924Advanced Li+ Battery-Pack Protectors 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.SRC, IC2, IC3, V CC to BN.......................................-0.3V to +28V IC1 to BN..................................................................-0.3V to +6V DSO , TKO , CGO to BN.............................-0.3V to (V SRC + 0.3V)B4P to B3P...............................................................-0.3V to +6V B3P to B2P...............................................................-0.3V to +6V B2P to B1P...............................................................-0.3V to +6V B1P to BN.................................................................-0.3V to +6V CTL, SHDN to PKN...................................................-0.3V to +6VPKN to BN ...................................................................-2V to +2V ESD Protection on All Pins...............................................±2000V Continuous Power Dissipation (T A = +70°C)16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature......................................................+150°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°CELECTRICAL CHARACTERISTICS(V SRC = V B4P + 0.1V, each battery cell voltage (V CELL )= 3.6V, V CTL = V SHDN = V PKN , T A = 0°C to +85°C , unless otherwise noted.MAX1894/MAX1924Advanced Li+ Battery-Pack Protectors_______________________________________________________________________________________3ELECTRICAL CHARACTERISTICS (continued)(V SRC = V B4P + 0.1V, each battery cell voltage (V CELL ) = 3.6V, V CTL = V SHDN = V PKN , T A = 0°C to +85°C , unless otherwise noted.M A X 1894/M A X 1924Advanced Li+ Battery-Pack Protectors 4_______________________________________________________________________________________Note 2:Typical supply current for the top cell during the 0.5ms sampling period.Note 3:Input bias current for this measurement is valid when all cell voltages are equal and the measurement is made over a timegreater than 3 seconds.Note 4:Each cell voltage is sampled individually and a differential measurement is made (V B4P - V B3P , V B3P - V B2P , V B2P - V B1P ,and V B1P - BN).Note 5:V PIN represents V DSO , V CGO , or V TKO .Note 6:Inputs to SHDN and CTL pins are referred to PKN.Note 7:Measurements are with respect to V SRC .ELECTRICAL CHARACTERISTICSMAX1894/MAX1924Advanced Li+ Battery-Pack Protectors_______________________________________________________________________________________5Typical Operating Characteristics(T A = +25°C, unless otherwise noted.)0.40.50.60.70.80.91.01.11.2-40-1510356085SHUTDOWN SUPPLY CURRENTvs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )603510-151020304050-40852.2902.2952.3002.3052.310-4010-15356085UNDERVOLTAGE THRESHOLDvs. TEMPERATURETEMPERATURE (°C)C E L L V O L T A G E (V )4.3404.3454.3504.3554.360-4010-15356085OVERVOLTAGE THRESHOLDvs. TEMPERATURETEMPERATURE (°C)C E L L V O L T A G E (V )709080110100120130-4085CHARGE-CURRENT FAULT THRESHOLD vs. TEMPERATURETEMPERATURE (°C)V B N - V P K N (m V )10-153560CHARGE-CURRENT FAULT RECOVERY THRESHOLD vs. TEMPERATUREM A X 1894 t o c 06TEMPERATURE (°C)V B 4P - V S R C (m V )6035-15103040506070809010020-4085DISCHARGE-CURRENT FAULT THRESHOLDvs. TEMPERATUREM A X 1894 t o c 07TEMPERATURE (°C)V P K N - V B N (m V )603510-15140145150155135-40852030405060708090100-40-1510356085DISCHARGE-CURRENT FAULT RECOVERYTHRESHOLD vs. TEMPERATUREM A X 1894 t o c 08TEMPERATURE (°C)V B 4P - V S R C (m V )415410405400395-4010-15356085PACK-SHORT CURRENT FAULT THRESHOLD vs. TEMPERATUREM A X 1894 t o c 09TEMPERATURE (°C)V P K N - V B N (m V )M A X 1894/M A X 1924Advanced Li+ Battery-Pack ProtectorsDISCHARGE-CURRENT FAULT TIMINGMAX1894 toc10V PKN - V BN 100mV/div 0DSO 5V/div1ms/divCHARGE-CURRENT FAULT TIMINGMAX1894 toc11V PKN - V BN 100mV/div001ms/divCGO 5V/div PACK-SHORT CURRENT FAULT TIMINGMAX1894 toc12V PKN - V BN 200mV/div 0100µs/divDSO 5V/divTypical Operating Characteristics (continued)(T A = +25°C, unless otherwise noted.)MAX1894/MAX1924Advanced Li+ Battery-Pack Protectors_______________________________________________________________________________________7Detailed DescriptionThe MAX1894/MAX1924 battery-pack protectors super-vise the charging and discharging process of Li+ cells.Designed for 3-series (MAX1924V) and 4-series (MAX1894X/MAX1924X) applications, these devices monitor the voltage across each cell to provide protec-tion against undervoltage, overvoltage, and overcurrent damage.Output pins CGO , TKO , and DSO control external MOSFET gates. These MOSFETs, in turn, control the fast-charging, trickle-charging, and discharge process-es of the battery pack (Figure 1).Modes of OperationShutdown ModeThe MAX1894/MAX1924 go into shutdown mode under two conditions: the SHDN pin is driven high without a charger applied, or a battery cell undervoltage fault is detected, also without a charger applied. In shutdown mode, the device consumes 0.8µA (typ) on the V CC pin and all MOSFETs are off. The MAX1894/MAX1924 stay in shutdown mode as long as no charging voltage is applied to the battery pack (V SRC is less than the pack voltage). When the battery pack is connected to a charger (V SRC > V B4P + 0.1V) and the pack voltage is above 4.5V, the device goes into normal operating mode and begins monitoring the pack (see Figure 2).Normal ModeIn the normal mode of operation, the MAX1894/MAX1924are in either a standby mode (29µA typ) or sample mode (160µA typ). The device enters the standby mode from shutdown mode. The standby mode lasts for 79ms; then the device goes into the sample mode. During sample mode, the MAX1894/MAX1924 check each cell for over-voltage and undervoltage. Sample mode lasts for 0.5ms;then the MAX1894/MAX1924 return to standby mode.During sample mode, the MAX1894/MAX1924 do not intro-duce cell mismatch.During normal mode operation, the MAX1894/MAX1924continuously monitor the voltage across R SENSE for charge or discharge current faults, or battery pack-short faults.Protection FeaturesOvervoltage ProtectionThe MAX1894/MAX1924 provide overvoltage protection to avoid overcharging cells. When an overvoltage fault is detected in four consecutive samples, CGO and TKO go high, stopping the charging process. The MAX1894/MAX1924 continue to sample the cell volt-ages, and if no overvoltage is detected, CGO and TKOMAX1924 also includes a hysteresis of 200mV.The overvoltage threshold is preprogrammed and requires no external components. The overvoltage thresh-old is factory set at 4.25V (typ) for the MAX1894 and 4.35V (typ) for the MAX1924. Contact Maxim for more information on threshold levels between 4V and 4.4V.Undervoltage ProtectionThe MAX1894/MAX1924 provide undervoltage protec-tion to avoid overdischarging the cells. With no battery charger present, and an undervoltage fault is detected in four consecutive samples, DSO , CGO , and TKO go high and the device goes into shutdown mode (see Figure 4).If a battery charger is applied to the battery pack and one or more cells are below V UV_TH , then only TKO goes low, allowing trickle-charge current to flow. If no undervoltage is detected in any sample, DSO , CGO ,and TKO all go low.The undervoltage threshold is preprogrammed at 2.30V (typ). Contact Maxim for more information on threshold levels between 2V and 3.2V.Charge-Current Fault ProtectionThe MAX1894/MAX1924 protect against excessive charge current by monitoring the voltage developed across R SENSE . R SENSE is connected between BN and PKN. If V RSENSE exceeds the charge-current fault threshold (V OC_TH , typically 100mV) for more than 3ms,the charge current comparator is tripped, setting CGO and TKO high.The charge-current fault condition is latched and is not reset until the MAX1894/MAX1924 detect a reversal inM A X 1894/M A X 1924Advanced Li+ Battery-Pack Protectors 8_______________________________________________________________________________________the direction of current flow. To reverse the current flow,the charger has to be removed (Figure 5). The sustain-ing condition for the latch is a 100mV (max) voltage drop across SRC and B4P. Since the charge-current fault threshold between BN and PKN is also 100mV (typ), the R DS_ON of the overcharge protection MOSFET must be greater than the sense resistor in order to ensure a latched state.Discharge-Current Fault ProtectionThe MAX1894/MAX1924 protect against excessive dis-charge-current by monitoring the voltage developed across R SENSE . If V RSENSE exceeds the discharge-cur-rent fault threshold (V OD_TH , typically 145mV) for morethan 3ms, the discharge-current comparator is tripped,setting DSO , CGO , and TKO high.Discharge-current fault is latched and is not reset until the MAX1894/MAX1924 detect a reversal in the direc-tion of current flow. To reverse the current flow, a charger must be applied (Figure 6).Pack-Short Current Fault ProtectionThe MAX1894/MAX1924 protect against a shorted pack by monitoring the voltage developed across R SENSE . If V RSENSE exceeds the pack-short threshold (V PS_TH , typically 405mV) for more than 450µs, the pack-short comparator is tripped, setting CGO , DSO ,and TKO high.Figure 1. Typical Applications Circuit with Trickle ChargeMAX1894/MAX1924Advanced Li+ Battery-Pack Protectors_______________________________________________________________________________________9Pack-short current fault is latched and is not reset until the MAX1894/MAX1924 detect a reversal in the direc-tion of current flow. A charger must be applied to reverse the current flow (Figure 7).Design ProcedureFast and Trickle-Charge PathsThe MAX1894/MAX1924 offer the designer the flexibility of two charging paths: a fast charging path and a trick-le-charge path (see Figure 1). Trickle charging is enabled and TKO is set low when one or more cells are belows V UV_TH .Figure 3. Shutdown and Control Pin Flow ChartsFigure 2. Undervoltage and Overvoltage Protection Flow ChartM A X 1894/M A X 1924Advanced Li+ Battery-Pack ProtectorsMAX1894/MAX1924Advanced Li+ Battery-Pack Protectors______________________________________________________________________________________11Set the nominal values of the trickle charge current by selecting resistor R TKO based on the following equation:R TKO = (V CHRG - VP ACK )/I TKO where V CHRG is the charger output voltage, V PACK is the battery-pack voltage, and I TKO is the trickle-charge current.When the trickle-charge option is not used, float CGO and connect TKO to the gate of the overcharge protec-tion MOSFET (see Figure 9). When a charger is applied and the voltage on one or more cells is less than V UV_TH , the MAX1894/MAX1924 modulate the TKO out-put until all cells exceed V UV_TH .Protection FET DriversAll three external MOSFETs have their source pins con-nected to the SRC pin. When a MOSFET is turned off, FET drivers pull the gate to the SRC voltage. Additional exter-nal pullup resistors are not needed. When the MOSFET is turned on, the V GS is limited to -14V by a clamp circuit built in the drivers. This allows use of MOSFETs with maxi-mum V GS of -20V. All three drivers have the same circuit-ry and drive capability. The quiescent current in normal operation is less than 3µA per driver.R SENSE SelectionAll current faults are detected using a current-sense resistor connected between BN and PKN. The value of this resistor sets the fault current levels. Charge-current fault is given by:Discharge-current fault is given by:Pack-short current fault is given by:Select R SENSE to obtain the desired fault current levels.For example, a 20m ΩR SENSE sets the charge current fault at 5A. Choose an R SENSE that can withstand the dissipation during normal operation and current faultconditions. For example, pack-short current is given by:Figure 5. Charge-Current FaultFigure 6. Discharge-Current FaultM A X 1894/M A X 1924Advanced Li+ Battery-Pack Protectors where N S is the number of cells in series, N P is number of cells in parallel, and V CELL is the cell voltage.Dissipation during pack-short current fault condition is given by:The R SENSE chosen should be able to withstand P PS dissipation. Verify power dissipation in normal operation and other current fault conditions as well.Choosing External MOSFETsThe external P-channel MOSFETs act as switches to enable or disable charging and discharging of batteries.Different P-channel MOSFETs may be selected depend-ing on the charge and discharge currents anticipated.In most applications, the requirements for fast-charge and discharge MOSFETs are similar and the same typeof MOSFETs can be used. The trickle-charge MOSFET can be a small-signal type to minimize cost.The MAX1894/MAX1924 MOSFET drivers have a V GS clamp of -14V typical and MOSFETs with maximum V GS of -20V can be used. MOSFETs must have a V DS greater than the maximum pack voltage.The power dissipation in the MOSFETs is given by:The MOSFET should be chosen to withstand power dis-sipation during normal operation and all current fault conditions. Additional MOSFETs can be added in paral-lel to help these requirements. Table 3 lists some suit-able MOSFETs in a small SO-8 package.Decoupling ConsiderationsThe MAX1894/MAX1924 must have a reliable V CC bias to function properly. A severe overload, such as a short circuit at the pack terminals, can collapse the battery-pack voltage below the V CC undervoltage lockout threshold. The use of a diode-capacitor peak detector on the V CC input ensures continued operation during voltage transients on the battery (Figure 1). Since the MAX1894/MAX1924 typically consume only 30µA, D1and C6 can be small, low-cost components. A 30V Schottky diode with a few mA current capability and a 0.1µF capacitor are sufficient.The MAX1894/MAX1924 continuously monitor the differ-ential voltage between the B4P and SRC inputs to detect the application of a charger. RC filters with simi-lar time constants must be added to both inputs to ensure the differential voltage is not corrupted by noise.P I R DSON=2P I R PS PS SENSE=×()212______________________________________________________________________________________MAX1894/MAX1924Advanced Li+ Battery-Pack Protectors______________________________________________________________________________________13Resistors in series with each B_P pin are recommend-ed to limit the current in case there is a short between adjacent B_P pins (see Figure 1).The intermediate cell input bias current is typically 0.5nA. A 1k Ωresistor in series with any intermediate cell moves the overvoltage trip point by typically 0.5mV,which is insignificant compared to the ±25mV tolerance in the overvoltage threshold. The top cell input bias cur-rent during sampling period is typically 60µA. To reduce the voltage change on the top cell input due to sampling current, a filter resistance of 10Ωto 50Ωshould be added in series with the top cell. To attain the desired filter characteristics, the capacitance across the two top cell input pins should be 1µF.The MAX1894/MAX1924 have internal ESD diodes on each B_P pin for ESD protection up to 2kV. When high-er ESD ratings are needed, capacitors (typically 0.1µF)can be added across adjacent B_P pins (see Figure 1).The RC filters improve the device immunity to ESD and filter the noise spikes on B1P –B4P to prevent the MAX1894/MAX1924 from being triggered and latched prematurely by noise spikes.Control Pins SHDN and CTLSHDN and CTL allow external logic or microprocessors to control the MAX1894/MAX1924 gate drivers. Drive CTL high to turn off the three protection MOSFETs: DSO ,CGO , and TKO . Drive SHDN high to force the MAX1894/MAX1924 into shutdown mode (with no charger applied).SHDN and CTL do not affect the state machine. Toggling these two pins does not change the state or reset any fault conditions. If external control circuitry or a micro-processor is not used, connect SHDN and CTL to PKN.Layout ConsiderationsG ood layout is important to minimize the effects of noise on the system and to ensure accurate voltage and current measurements. Use the appropriate trace widths for the high-current paths and keep traces short to minimize parasitic inductance and capacitance.Minimize current-sense resistor trace lengths and make use of Kelvin connections to the resistor. Provide ade-quate space and board area for the external MOSFETs and sense resistor to dissipate the heat required. Place RC filters close to B1P –B4P pins.Figure 7. Pack-Short Current FaultChip InformationTRANSISTOR COUNT: 4259M A X 1894/M A X 1924Advanced Li+ Battery-Pack Protectors 14______________________________________________________________________________________Figure 8. Simplified Functional DiagramAdvanced Li+ Battery-Pack Protectors______________________________________________________________________________________15M A X 1894/M A X 1924Advanced Li+ Battery-Pack Protectors Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.16____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2002 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.Package Information(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to /packages .)。

General DescriptionThe MAX3222E/MAX3232E/MAX3237E/MAX3241E are 3V-powered EIA/TIA-232 and V.28/V.24 communications interfaces with low power requirements, high data-rate capabilities, and enhanced electrostatic discharge (ESD)protection. All transmitter outputs and receiver inputs are protected to ±15kV using IEC 1000-4-2 Air-G ap Discharge, ±8kV using IEC 1000-4-2 Contact Discharge,and ±15kV using the Human Body Model. In addition, the MAX3237E’s logic and receiver I/O pins are protected to the above ESD standards.The transceivers have a proprietary low-dropout transmit-ter output stage, delivering true RS-232 performance from a +3.0V to +5.5V supply with a dual charge pump. The charge pump requires only four small 0.1µF capacitors for operation from a +3.3V supply. Each device is guaran-teed to run at data rates of 250kbps while maintaining RS-232 output levels. The MAX3237E is guaranteed to run at data rates of 250kbps in the normal operating mode and 1Mbps in the MegaBaud™ operating mode while main-taining RS-232-compliant output levels.The MAX3222E/MAX3232E have two receivers and two drivers. The MAX3222E features a 1µA shutdown mode that reduces power consumption and extends battery life in portable systems. Its receivers can remain active in shutdown mode, allowing external devices such as modems to be monitored using only 1µA supply current.Both the MAX3222E and MAX3232E are pin, package,and functionally compatible with the industry-standard MAX242 and MAX232, respectively.The MAX3241E is a complete serial port (three drivers/five receivers) designed for notebook and sub-notebook computers. The MAX3237E (five drivers/three receivers) is ideal for peripheral applications that require fast data transfer. Both devices feature a shutdown mode in which all receivers can remain active while using a supply current of only 1µA (MAX3241E) or 10nA (MAX3237E). The MAX3237E/MAX3241E have additional receiver outputs that always remain active.The MAX3222E, MAX3232E, and MAX3241E are avail-able in space-saving SO, SSOP, and TSSOP packages.The MAX3237E is available in an SSOP package.________________________ApplicationsBattery-Powered Equipment PrintersCell PhonesSmart Phones Cell-Phone Data Cables xDSL ModemsNotebook, Subnotebook, and Palmtop ComputersFeatureso ESD Protection for RS-232 I/O Pins(MAX3222E/MAX3232E/MAX3237E/MAX3241E)±15kV—Human Body Model±8kV—IEC 1000-4-2, Contact Discharge ±15kV—IEC 1000-4-2, Air-Gap Discharge o ESD Protection For All Logic and Receiver I/O Pins (MAX3237E)±15kV—Human Body Model±8kV—IEC 1000-4-2, Contact Discharge ±15kV—IEC 1000-4-2, Air-Gap Discharge o Guaranteed Data Rate250kbps (MAX3222E/MAX3232E/MAX3241E and MAX3237E, Normal Operation)1Mbps (MAX3237E, MegaBaud Operation)o Latchup Freeo Low-Power Shutdown with Receivers Active1µA (MAX3222E/MAX3241E)10nA (MAX3237E)o Flow-Through Pinout (MAX3237E)o Guaranteed Mouse Driveability (MAX3241E)o Meets EIA/TIA-232 Specifications Down to 3.0VMAX3222E/MAX3232E/MAX3237E/MAX3241E †±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers________________________________________________________________Maxim Integrated Products119-1298; Rev 5; 3/02MegaBaud is a trademark of Maxim Integrated Products, Inc.†Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761; and other patents pending.For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .M A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 TransceiversABSOLUTE MAXIMUM RATINGSELECTRICAL CHARACTERISTICSStresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.V CC to GND..............................................................-0.3V to +6V V+ to GND (Note 1)..................................................-0.3V to +7V V- to GND (Note 1)...................................................+0.3V to -7V V+ + |V-| (Note 1).................................................................+13V Input VoltagesT_IN, EN , SHDN , MBAUD to GND ........................-0.3V to +6V R_IN to GND.....................................................................±25V Output VoltagesT_OUT to GND...............................................................±13.2V R_OUT, R_OUTB (MAX3241E)................-0.3V to (V CC + 0.3V)Short-Circuit Duration, T_OUT to GND.......................Continuous Continuous Power Dissipation (T A = +70°C)16-Pin SSOP (derate 7.14mW/°C above +70°C)..........571mW 16-Pin Wide SO (derate 9.52mW/°C above +70°C).....762mW18-Pin Wide SO (derate 9.52mW/°C above +70°C).....762mW 18-Pin PDIP (derate 11.11mW/°C above +70°C)..........889mW 20-Pin TSSOP (derate 10.9mW/°C above +70°C)........879mW 20-Pin SSOP (derate 8.00mW/°C above +70°C)..........640mW 28-Pin SSOP (derate 9.52mW/°C above +70°C)..........762mW 28-Pin Wide SO (derate 12.50mW/°C above +70°C).............1W 28-Pin TSSOP (derate 12.8mW/°C above +70°C)......1026mW 32-pin QFN (derate 23.2mW/°C above +70°C).............1860mW Operating Temperature RangesMAX32_ _EC_ _...................................................0°C to +70°C MAX32_ _EE_ _.................................................-40°C to +85°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°CNote 1:V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.MAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 TransceiversELECTRICAL CHARACTERISTICS (continued)(V CC = +3.0V to +5.5V, C1–C4 = 0.1µF, T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.) (Note 2)(V CC = +3.0V to +5.5V, C1–C4 = 0.1µF, T A = T MIN to T MAX , unless otherwise noted. Typical values are at T A = +25°C.) (Note 2)__________________________________________Typical Operating Characteristics(V CC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3k Ωand C L , T A = +25°C, unless otherwise noted.)-6-5-4-3-2-10123456010002000300040005000MAX3222E/MAX3232ETRANSMITTER OUTPUT VOLTAGEvs. LOAD CAPACITANCELOAD CAPACITANCE (pF)T R A N S M I T T E R O U T P U T V O L T A G E (V )624108141216010002000300040005000MAX3222E/MAX3232ESLEW RATE vs. LOAD CAPACITANCELOAD CAPACITANCE (pF)S L E W R A T E (V /µs )2520155103530404520001000300040005000MAX3222E/MAX3232E OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCELOAD CAPACITANCE (pF)S U P P L Y C U R R E N T (m A )M A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers4_______________________________________________________________________________________TIMING CHARACTERISTICS —MAX3237ENote 2:MAX3222E/MAX3232E/MAX3241E: C1–C4 = 0.1µF tested at 3.3V ±10%; C1 = 0.047µF, C2, C3, C4 = 0.33µF tested at 5.0V±10%. MAX3237E: C1–C4 = 0.1µF tested at 3.3V ±5%, C1–C4 = 0.22µF tested at 3.3V ±10%; C1 = 0.047µF, C2, C3, C4 =0.33µF tested at 5.0V ±10%.Note 3:The MAX3237E logic inputs have an active positive feedback resistor. The input current goes to zero when the inputs are atthe supply rails.Note 4:Transmitter skew is measured at the transmitter zero crosspoints.MAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers_______________________________________________________________________________________5-6-2-42046-5-31-135010001500500200025003000LOAD CAPACITANCE (pF)T R A N S M I T T E R O U T P U T V O L T A G E (V )MAX3237ETRANSMITTER OUTPUT VOLTAGEvs. LOAD CAPACITANCE010203050406070MAX3237ESLEW RATE vs. LOAD CAPACITANCE(MBAUD = V CC )LOAD CAPACITANCE (pF)S L E W R A T E (V /µs )500100015002000-7.5-5.0-2.502.55.07.5MAX3237ETRANSMITTER OUTPUT VOLTAGE vs. LOAD CAPACITANCE (MBAUD = V CC )LOAD CAPACITANCE (pF)T R A N S M I T T E R O U T P U T V O L T A G E (V )50010001500200024681012MAX3237ESLEW RATE vs. LOAD CAPACITANCE(MBAUD = GND)LOAD CAPACITANCE (pF)S L E W R A T E (V /µs )100015005002000250030001020304050MAX3237ESUPPLY CURRENT vs. LOAD CAPACITANCE WHEN TRANSMITTING DATA (MBAUD = GND)LOAD CAPACITANCE (pF)S U P P L Y C U R R E N T (m A )1000150050020002500300020604080100MAX3237ETRANSMITTER SKEW vs. LOAD CAPACITANCE(MBAUD = V CC )LOAD CAPACITANCE (pF)100015005002000T R A N S M I T T E R S K E W (n s )Typical Operating Characteristics (continued)(V CC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3k Ωand C L, T A = +25°C, unless otherwise noted.)-6-5-4-3-2-10123456010002000300040005000MAX3241ETRANSMITTER OUTPUT VOLTAGEvs. LOAD CAPACITANCELOAD CAPACITANCE (pF)T R A N S M I T T E R O U T P U T V O L T A G E (V )302010405060020001000300040005000MAX3241EOPERATING SUPPLY CURRENT vs. LOAD CAPACITANCELOAD CAPACITANCE (pF)S U P P L Y C U R R E N T (m A )04286121014010002000300040005000MAX3241ESLEW RATE vs. LOAD CAPACITANCEM A X 3237E t o c 05LOAD CAPACITANCE (pF)S L E W R A T E (V /µs )Pin DescriptionM A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 TransceiversTypical Operating Characteristics (continued)(V CC = +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3k Ωand C L , T A = +25°C, unless otherwise noted.)-6-2-42046-3-51-1352.03.0 3.52.54.0 4.55.0SUPPLY VOLTAGE (V)T R A N S M I T T E R O U T P U T V O L T A G E (V )MAX3237ETRANSMITTER OUTPUT VOLTAGE vs.SUPPLY VOLTAGE (MBAUD = GND)10203040502.0MAX3237ESUPPLY CURRENT vs.SUPPLY VOLTAGE (MBAUD = GND)SUPPLY VOLTAGE (V)S U P P L Y C U R R E N T (m A )3.03.52.54.04.55.0MAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers_______________________________________________________________________________________7Figure 1. Slew-Rate Test CircuitsM A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers_______________Detailed DescriptionDual Charge-Pump Voltage ConverterThe MAX3222E/MAX3232E/MAX3237E/MAX3241E ’s internal power supply consists of a regulated dual charge pump that provides output voltages of +5.5V (doubling charge pump) and -5.5V (inverting charge pump), over the 3.0V to 5.5V V CC range. The charge pump operates in discontinuous mode; if the output voltages are less than 5.5V, the charge pump is enabled, and if the output voltages exceed 5.5V, the charge pump is disabled. Each charge pump requires a flying capacitor (C1, C2) and a reservoir capacitor (C3, C4) to generate the V+ and V- supplies (Figure 1).RS-232 TransmittersThe transmitters are inverting level translators that con-vert TTL/CMOS-logic levels to ±5.0V EIA/TIA-232 com-pliant levels.The MAX3222E/MAX3232E/MAX3237E/MAX3241E transmitters guarantee a 250kbps data rate with worst-case loads of 3k Ωin parallel with 1000pF, providing compatibility with PC-to-PC communication software (such as LapLink ™). Transmitters can be paralleled to drive multiple receivers or mice.The MAX3222E/MAX3237E/MAX3241E ’s transmitters are disabled and the outputs are forced into a high-imped-ance state when the device is in shutdown mode (SHDN =GND). The MAX3222E/MAX3232E/MAX3237E/MAX3241E permit the outputs to be driven up to ±12V in shutdown.The MAX3222E/MAX3232E/MAX3241E transmitter inputs do not have pullup resistors. Connect unused inputs to G ND or V CC . The MAX3237E ’s transmitter inputs have a 400k Ωactive positive feedback resistor,allowing unused inputs to be left unconnected.MAX3237E MegaBaud OperationFor higher-speed serial communications, the MAX3237E features MegaBaud operation. In MegaBaud operating mode (MBAUD = V CC ), the MAX3237E transmitters guarantee a 1Mbps data rate with worst-case loads of 3k Ωin parallel with 250pF for 3.0V < V CC < 4.5V. For 5V ±10% operation, the MAX3237E transmitters guarantee a 1Mbps data rate into worst-case loads of 3k Ωin parallel with 1000pF.RS-232 ReceiversThe receivers convert RS-232 signals to CMOS-logic output levels. The MAX3222E/MAX3237E/MAX3241E receivers have inverting three-state outputs. Drive EN high to place the receiver(s) into a high-impedancestate. Receivers can be either active or inactive in shut-down (Table 1).The complementary outputs on the MAX3237E/MAX3241E (R_OUTB) are always active, regardless of the state of EN or SHDN . This allows the device to be used for ring indica-tor applications without forward biasing other devices con-nected to the receiver outputs. This is ideal for systems where V CC drops to 0 in shutdown to accommodate peripherals such as UARTs (Figure 2).MAX3222E/MAX3237E/MAX3241EShutdown ModeSupply current falls to less than 1µA in shutdown mode (SHDN = low). The MAX3237E ’s supply current falls to10nA (typ) when all receiver inputs are in the invalid range (-0.3V < R_IN < +0.3). When shut down, the device ’s charge pumps are shut off, V+ is pulled down to V CC , V- is pulled to ground, and the transmitter outputs are disabled (high impedance). The time required to recover from shutdown is typically 100µs,as shown in Figure 3. Connect SHDN to V CC if the shut-down mode is not used. SHDN has no effect on R_OUT or R_OUTB (MAX3237E/MAX3241E).±15kV ESD ProtectionAs with all Maxim devices, ESD-protection structures are incorporated to protect against electrostatic dis-charges encountered during handling and assembly.The driver outputs and receiver inputs of the MAX3222E/MAX3232E/MAX3237E/MAX3241E have extra protection against static electricity. Maxim ’s engi-neers have developed state-of-the-art structures to pro-tect these pins against ESD of ±15kV without damage.The ESD structures withstand high ESD in all states:normal operation, shutdown, and powered down. After an ESD event, Maxim ’s E versions keep working without latchup, whereas competing RS-232 products can latch and must be powered down to remove latchup.Furthermore, the MAX3237E logic I/O pins also have ±15kV ESD protection. Protecting the logic I/O pins to ±15kV makes the MAX3237E ideal for data cable appli-cations.LapLink is a trademark of Traveling Software.8MAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers_______________________________________________________________________________________9ESD protection can be tested in various ways; the transmitter outputs and receiver inputs for the MAX3222E/MAX3232E/MAX3237E/MAX3241E are characterized for protection to the following limits:•±15kV using the Human Body Model•±8kV using the Contact Discharge method specified in IEC 1000-4-2•±15kV using IEC 1000-4-2’s Air-G ap Discharge method ESD Test ConditionsESD performance depends on a variety of conditions.Contact Maxim for a reliability report that documents test setup, test methodology, and test results.Human Body ModelFigure 4a shows the Human Body Model, and Figure 4b shows the current waveform it generates when dis-charged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of inter-est, which is then discharged into the test device through a 1.5k Ωresistor.IEC 1000-4-2The IEC 1000-4-2 standard covers ESD testing and per-formance of finished equipment; it does not specifically refer to integrated circuits. The MAX3222E/MAX3232E/MAX3237E/MAX3241E help you design equipment that meets Level 4 (the highest level) of IEC 1000-4-2, without the need for additional ESD-protection components.The major difference between tests done using the Human Body Model and IEC 1000-4-2 is higher peak current in IEC 1000-4-2 because series resistance is lower in the IEC 1000-4-2 model. Hence, the ESD with-stand voltage measured to IEC 1000-4-2 is generally lower than that measured using the Human Body Model. Figure 5a shows the IEC 1000-4-2 model, and Figure 5b shows the current waveform for the ±8kV IEC 1000-4-2 Level 4 ESD Contact Discharge test.The Air-G ap Discharge test involves approaching the device with a charged probe. The Contact DischargeFigure 2. Detection of RS-232 Activity when the UART andInterface are Shut Down; Comparison of MAX3237E/MAX3241E (b) with Previous Transceivers (a)40µs/divV CC = 3.3V C1–C4 = 0.1µFFigure 3. Transmitter Outputs Recovering from Shutdown or Powering UpM A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers10______________________________________________________________________________________method connects the probe to the device before the probe is energized.Machine ModelThe Machine Model for ESD tests all pins using a 200pF storage capacitor and zero discharge resis-tance. Its objective is to emulate the stress caused by contact that occurs with handling and assembly during manufacturing. All pins require this protection during manufacturing, not just RS-232 inputs and outputs.Therefore, after PC board assembly, the Machine Model is less relevant to I/O ports.Applications InformationCapacitor SelectionThe capacitor type used for C1–C4 is not critical for proper operation; polarized or nonpolarized capacitors can be used. The charge pump requires 0.1µF capaci-tors for 3.3V operation. For other supply voltages, see Table 2for required capacitor values. Do not use val-ues smaller than those listed in Table 2. Increasing the capacitor values (e.g., by a factor of 2) reduces ripple on the transmitter outputs and slightly reduces power consumption. C2, C3, and C4 can be increased without changing C1’s value. However, do not increase C1without also increasing the values of C2, C3, C4,and C BYPASS to maintain the proper ratios (C1 to the other capacitors).Figure 4a. Human Body ESD Test Model Figure 4b. Human Body Model Current WaveformFigure 5a. IEC 1000-4-2 ESD Test Model Figure 5b. IEC 1000-4-2 ESD Generator Current WaveformMAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers______________________________________________________________________________________11When using the minimum required capacitor values,make sure the capacitor value does not degrade excessively with temperature. If in doubt, use capaci-tors with a larger nominal value. The capacitor ’s equiv-alent series resistance (ESR), which usually rises at low temperatures, influences the amount of ripple on V+and V-.Power-Supply DecouplingIn most circumstances, a 0.1µF V CC bypass capacitor is adequate. In applications that are sensitive to power-supply noise, use a capacitor of the same value as charge-pump capacitor C1. Connect bypass capaci-tors as close to the IC as possible.Operation Down to 2.7VTransmitter outputs will meet EIA/TIA-562 levels of ±3.7V with supply voltages as low as 2.7V.Transmitter Outputs when Recovering from ShutdownFigure 3shows two transmitter outputs when recover-ing from shutdown mode. As they become active, the two transmitter outputs are shown going to opposite RS-232 levels (one transmitter input is high, the other is low). Each transmitter is loaded with 3k Ωin parallel with 2500pF. The transmitter outputs display no ringing or undesirable transients as they come out of shutdown.Note that the transmitters are enabled only when the magnitude of V- exceeds approximately -3V.Mouse DriveabilityThe MAX3241E has been specifically designed to power serial mice while operating from low-voltagepower supplies. It has been tested with leading mouse brands from manufacturers such as Microsoft and Logitech. The MAX3241E successfully drove all serial mice tested and met their respective current and volt-age requirements. Figure 6a shows the transmitter out-put voltages under increasing load current at 3.0V.Figure 6b shows a typical mouse connection using the MAX3241E.High Data RatesThe MAX3222E/MAX3232E/MAX3237E/MAX3241E maintain the RS-232 ±5.0V minimum transmitter output voltage even at high data rates. Figure 7shows a trans-mitter loopback test circuit. Figure 8shows a loopback test result at 120kbps, and Figure 9shows the same test at 250kbps. For Figure 8, all transmitters were driven simultaneously at 120kbps into RS-232 loads in parallel with 1000pF. For Figure 9, a single transmitter was driv-en at 250kbps, and all transmitters were loaded with an RS-232 receiver in parallel with 1000pF.The MAX3237 maintains the RS-232 ±5.0V minimum transmitter output voltage at data rates up to 1Mbps.Figure 10shows a loopback test result at 1Mbps with MBAUD = V CC . For Figure 10, all transmitters were loaded with an RS-232 receiver in parallel with 250pF.Interconnection with 3V and 5V LogicThe MAX3222E/MAX3232E/MAX3237E/MAX3241E can directly interface with various 5V logic families, includ-ing ACT and HCT CMOS. See Table 3for more infor-mation on possible combinations of interconnections.Figure 6a. MAX3241E Transmitter Output Voltage vs. Load Current per TransmitterM A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers12______________________________________________________________________________________Figure 6b. Mouse Driver Test CircuitMAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers______________________________________________________________________________________13Figure 7. Loopback Test Circuit2µs/divV CC = 3.3V C1–C4 = 0.1µFFigure 8. MAX3241E Loopback Test Result at 120kbps2µs/divV CC = 3.3V, C1–C4 = 0.1µFFigure 9. MAX3241E Loopback Test Result at 250kbpsT_INT_OUT5k ΩR_OUT400ns/divV CC = 3.3V C1–C4 = 0.1µFFigure 10. MAX3237E Loopback Test Result at 1000kbps (MBAUD = V CC )Table 3. Logic-Family Compatibility with Various Supply VoltagesM A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers14________________________________________________________________________________________________________________________________________________Pin ConfigurationsMAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers______________________________________________________________________________________15__________________________________________________Typical Operating CircuitsM A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers16___________________________________________________________________________________________________________________________Typical Operating Circuits (continued)MAX3222E/MAX3232E/MAX3237E/MAX3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers______________________________________________________________________________________17Ordering Information (continued)___________________Chip InformationTRANSISTOR COUNT:MAX3222E/MAX3232E: 1129MAX3237E: 2110MAX3241E: 1335M A X 3222E /M A X 3232E /M A X 3237E /M A X 3241E±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 Transceivers18______________________________________________________________________________________Package Information(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to /packages .)±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V ,Up to 1Mbps, True RS-232 TransceiversMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. N o circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.19____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600©2001 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.MAX3222E/MAX3232E/MAX3237E/MAX3241EPackage Information (continued)(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to /packages .)。

General DescriptionThe MAX220–MAX249 family of line drivers/receivers is intended for all EIA/TIA-232E and V.28/V.24 communica-tions interfaces, particularly applications where ±12V is not available.These parts are especially useful in battery-powered sys-tems, since their low-power shutdown mode reduces power dissipation to less than 5µW. The MAX225,MAX233, MAX235, and MAX245/MAX246/MAX247 use no external components and are recommended for appli-cations where printed circuit board space is critical.________________________ApplicationsPortable Computers Low-Power Modems Interface TranslationBattery-Powered RS-232 Systems Multidrop RS-232 NetworksNext-Generation Device Features♦For Low-Voltage, Integrated ESD ApplicationsMAX3222E/MAX3232E/MAX3237E/MAX3241E/MAX3246E: +3.0V to +5.5V, Low-Power, Up to 1Mbps, True RS-232 Transceivers Using Four 0.1µF External Capacitors (MAX3246E Available in a UCSP™Package)♦For Low-Cost ApplicationsMAX221E: ±15kV ESD-Protected, +5V, 1µA,Single RS-232 Transceiver with AutoShutdown™MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers________________________________________________________________Maxim Integrated Products 1Selection Table19-4323; Rev 15; 1/06Power No. of NominalSHDN RxPart Supply RS-232No. of Cap. Value & Three-Active in Data Rate Number (V)Drivers/Rx Ext. Caps (µF)State SHDN (kbps)FeaturesMAX220+52/240.047/0.33No —120Ultra-low-power, industry-standard pinout MAX222+52/2 4 0.1Yes —200Low-power shutdownMAX223 (MAX213)+54/54 1.0 (0.1)Yes ✔120MAX241 and receivers active in shutdown MAX225+55/50—Yes ✔120Available in SOMAX230 (MAX200)+55/04 1.0 (0.1)Yes —120 5 drivers with shutdownMAX231 (MAX201)+5 and2/2 2 1.0 (0.1)No —120Standard +5/+12V or battery supplies; +7.5 to +13.2same functions as MAX232MAX232 (MAX202)+52/24 1.0 (0.1)No —120 (64)Industry standardMAX232A+52/240.1No —200Higher slew rate, small caps MAX233 (MAX203)+52/20— No —120No external capsMAX233A+52/20—No —200No external caps, high slew rate MAX234 (MAX204)+54/04 1.0 (0.1)No —120Replaces 1488MAX235 (MAX205)+55/50—Yes —120No external capsMAX236 (MAX206)+54/34 1.0 (0.1)Yes —120Shutdown, three stateMAX237 (MAX207)+55/34 1.0 (0.1)No —120Complements IBM PC serial port MAX238 (MAX208)+54/44 1.0 (0.1)No —120Replaces 1488 and 1489MAX239 (MAX209)+5 and3/52 1.0 (0.1)No —120Standard +5/+12V or battery supplies;+7.5 to +13.2single-package solution for IBM PC serial port MAX240+55/54 1.0Yes —120DIP or flatpack package MAX241 (MAX211)+54/54 1.0 (0.1)Yes —120Complete IBM PC serial port MAX242+52/240.1Yes ✔200Separate shutdown and enableMAX243+52/240.1No —200Open-line detection simplifies cabling MAX244+58/104 1.0No —120High slew rateMAX245+58/100—Yes ✔120High slew rate, int. caps, two shutdown modes MAX246+58/100—Yes ✔120High slew rate, int. caps, three shutdown modes MAX247+58/90—Yes ✔120High slew rate, int. caps, nine operating modes MAX248+58/84 1.0Yes ✔120High slew rate, selective half-chip enables MAX249+56/1041.0Yes✔120Available in quad flatpack packageFor pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering InformationOrdering Information continued at end of data sheet.*Contact factory for dice specifications.AutoShutdown and UCSP are trademarks of Maxim Integrated Products, Inc.M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 2_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS—MAX220/222/232A/233A/242/243ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243Note 1:For the MAX220, V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.Note 2:Input voltage measured with T OUT in high-impedance state, SHDN or V CC = 0V.Note 3:Maximum reflow temperature for the MAX233A is +225°C.Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.Supply Voltage (V CC )...............................................-0.3V to +6V V+ (Note 1)..................................................(V CC - 0.3V) to +14V V- (Note 1).............................................................+0.3V to +14V Input VoltagesT IN ..............................................................-0.3V to (V CC - 0.3V)R IN (Except MAX220)........................................................±30V R IN (MAX220).....................................................................±25V T OUT (Except MAX220) (Note 2).......................................±15V T OUT (MAX220)...............................................................±13.2V Output VoltagesT OUT ...................................................................................±15V R OUT .........................................................-0.3V to (V CC + 0.3V)Driver/Receiver Output Short Circuited to GND.........Continuous Continuous Power Dissipation (T A = +70°C)16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)..842mW18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)..889mW 20-Pin Plastic DIP (derate 8.00mW/°C above +70°C)..440mW 16-Pin Narrow SO (derate 8.70mW/°C above +70°C)...696mW 16-Pin Wide SO (derate 9.52mW/°C above +70°C)......762mW 18-Pin Wide SO (derate 9.52mW/°C above +70°C)......762mW 20-Pin Wide SO (derate 10.00mW/°C above +70°C)....800mW 20-Pin SSOP (derate 8.00mW/°C above +70°C)..........640mW 16-Pin CERDIP (derate 10.00mW/°C above +70°C).....800mW 18-Pin CERDIP (derate 10.53mW/°C above +70°C).....842mW Operating Temperature RangesMAX2_ _AC_ _, MAX2_ _C_ _.............................0°C to +70°C MAX2_ _AE_ _, MAX2_ _E_ _..........................-40°C to +85°C MAX2_ _AM_ _, MAX2_ _M_ _.......................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10s) (Note 3)...................+300°CMAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________3Note 4:MAX243 R2OUT IN ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 4_________________________________________________________________________________________________________________________________Typical Operating CharacteristicsMAX220/MAX222/MAX232A/MAX233A/MAX242/MAX243108-1051525OUTPUT VOLTAGE vs. LOAD CURRENT-4-6-8-2642LOAD CURRENT (mA)O U T P U T V O L T A G E (V )1002011104104060AVAILABLE OUTPUT CURRENTvs. DATA RATE65798DATA RATE (kb/s)O U T P U T C U R R E N T (m A )203050+10V-10VMAX222/MAX242ON-TIME EXITING SHUTDOWN+5V +5V 0V0V 500μs/div V +, V - V O L T A G E (V )ELECTRICAL CHARACTERISTICS—MAX220/222/232A/233A/242/243 (continued)(V CC = +5V ±10%, C1–C4 = 0.1µF‚ MAX220, C1 = 0.047µF, C2–C4 = 0.33µF, T A = T MIN to T MAX ‚ unless otherwise noted.)MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________5V CC ...........................................................................-0.3V to +6V V+................................................................(V CC - 0.3V) to +14V V-............................................................................+0.3V to -14V Input VoltagesT IN ............................................................-0.3V to (V CC + 0.3V)R IN ......................................................................................±30V Output VoltagesT OUT ...................................................(V+ + 0.3V) to (V- - 0.3V)R OUT .........................................................-0.3V to (V CC + 0.3V)Short-Circuit Duration, T OUT ......................................Continuous Continuous Power Dissipation (T A = +70°C)14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)....800mW 16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)....842mW 20-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW 24-Pin Narrow Plastic DIP(derate 13.33mW/°C above +70°C)..........1.07W24-Pin Plastic DIP (derate 9.09mW/°C above +70°C)......500mW 16-Pin Wide SO (derate 9.52mW/°C above +70°C).........762mW20-Pin Wide SO (derate 10.00mW/°C above +70°C).......800mW 24-Pin Wide SO (derate 11.76mW/°C above +70°C).......941mW 28-Pin Wide SO (derate 12.50mW/°C above +70°C) .............1W 44-Pin Plastic FP (derate 11.11mW/°C above +70°C).....889mW 14-Pin CERDIP (derate 9.09mW/°C above +70°C)..........727mW 16-Pin CERDIP (derate 10.00mW/°C above +70°C)........800mW 20-Pin CERDIP (derate 11.11mW/°C above +70°C)........889mW 24-Pin Narrow CERDIP(derate 12.50mW/°C above +70°C)..............1W24-Pin Sidebraze (derate 20.0mW/°C above +70°C)..........1.6W 28-Pin SSOP (derate 9.52mW/°C above +70°C).............762mW Operating Temperature RangesMAX2 _ _ C _ _......................................................0°C to +70°C MAX2 _ _ E _ _...................................................-40°C to +85°C MAX2 _ _ M _ _......................................................-55°C to +125°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering, 10s) (Note 4)...................+300°CABSOLUTE MAXIMUM RATINGS—MAX223/MAX230–MAX241ELECTRICAL CHARACTERISTICS—MAX223/MAX230–MAX241(MAX223/230/232/234/236/237/238/240/241, V CC = +5V ±10; MAX233/MAX235, V CC = 5V ±5%‚ C1–C4 = 1.0µF; MAX231/MAX239,V CC = 5V ±10%; V+ = 7.5V to 13.2V; T A = T MIN to T MAX ; unless otherwise noted.)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.Note 4:Maximum reflow temperature for the MAX233/MAX235 is +225°C.M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 6_______________________________________________________________________________________ELECTRICAL CHARACTERISTICS—MAX223/MAX230–MAX241 (continued)(MAX223/230/232/234/236/237/238/240/241, V CC = +5V ±10; MAX233/MAX235, V CC = 5V ±5%‚ C1–C4 = 1.0µF; MAX231/MAX239,V CC = 5V ±10%; V+ = 7.5V to 13.2V; T A = T MIN to T MAX ; unless otherwise noted.)MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________78.56.54.55.5TRANSMITTER OUTPUT VOLTAGE (V OH ) vs. V CC7.08.0V CC (V)V O H (V )5.07.57.46.02500TRANSMITTER OUTPUT VOLTAGE (V OH )vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES6.46.27.27.0LOAD CAPACITANCE (pF)V O H (V )1500100050020006.86.612.04.02500TRANSMITTER SLEW RATE vs. LOAD CAPACITANCE6.05.011.09.010.0LOAD CAPACITANCE (pF)S L E W R A T E (V /μs )1500100050020008.07.0-6.0-9.04.55.5TRANSMITTER OUTPUT VOLTAGE (V OL ) vs. V CC-8.0-8.5-6.5-7.0V CC (V)V O L (V )5.0-7.5-6.0-7.62500TRANSMITTER OUTPUT VOLTAGE (V OL )vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES-7.0-7.2-7.4-6.2-6.4LOAD CAPACITANCE (pF)V O L (V )150010005002000-6.6-6.810-105101520253035404550TRANSMITTER OUTPUT VOLTAGE (V+, V-)vs. LOAD CURRENT-2-6-4-886CURRENT (mA)V +, V - (V )420__________________________________________Typical Operating CharacteristicsMAX223/MAX230–MAX241*SHUTDOWN POLARITY IS REVERSED FOR NON MAX241 PARTSV+, V- WHEN EXITING SHUTDOWN(1μF CAPACITORS)MAX220-13SHDN*V-O V+500ms/divM A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 8_______________________________________________________________________________________ABSOLUTE MAXIMUM RATINGS—MAX225/MAX244–MAX249ELECTRICAL CHARACTERISTICS—MAX225/MAX244–MAX249(MAX225, V CC = 5.0V ±5%; MAX244–MAX249, V CC = +5.0V ±10%, external capacitors C1–C4 = 1µF; T A = T MIN to T MAX ; unless oth-erwise noted.)Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.Supply Voltage (V CC )...............................................-0.3V to +6V Input VoltagesT IN ‚ ENA , ENB , ENR , ENT , ENRA ,ENRB , ENTA , ENTB ..................................-0.3V to (V CC + 0.3V)R IN .....................................................................................±25V T OUT (Note 5).....................................................................±15V R OUT ........................................................-0.3V to (V CC + 0.3V)Short Circuit (one output at a time)T OUT to GND............................................................Continuous R OUT to GND............................................................ContinuousContinuous Power Dissipation (T A = +70°C)28-Pin Wide SO (derate 12.50mW/°C above +70°C).............1W 40-Pin Plastic DIP (derate 11.11mW/°C above +70°C)...611mW 44-Pin PLCC (derate 13.33mW/°C above +70°C)...........1.07W Operating Temperature RangesMAX225C_ _, MAX24_C_ _ ..................................0°C to +70°C MAX225E_ _, MAX24_E_ _ ...............................-40°C to +85°C Storage Temperature Range.............................-65°C to +160°C Lead Temperature (soldering,10s) (Note 6)....................+300°CNote 5:Input voltage measured with transmitter output in a high-impedance state, shutdown, or V CC = 0V.Note 6:Maximum reflow temperature for the MAX225/MAX245/MAX246/MAX247 is +225°C.MAX220–MAX249+5V-Powered, Multichannel RS-232Drivers/Receivers_______________________________________________________________________________________9Note 7:The 300Ωminimum specification complies with EIA/TIA-232E, but the actual resistance when in shutdown mode or V CC =0V is 10M Ωas is implied by the leakage specification.ELECTRICAL CHARACTERISTICS—MAX225/MAX244–MAX249 (continued)(MAX225, V CC = 5.0V ±5%; MAX244–MAX249, V CC = +5.0V ±10%, external capacitors C1–C4 = 1µF; T A = T MIN to T MAX ; unless oth-erwise noted.)M A X 220–M A X 249+5V-Powered, Multichannel RS-232Drivers/Receivers 10________________________________________________________________________________________________________________________________Typical Operating CharacteristicsMAX225/MAX244–MAX24918212345TRANSMITTER SLEW RATE vs. LOAD CAPACITANCE86416LOAD CAPACITANCE (nF)T R A N S M I T T E R S L E W R A T E (V /μs )14121010-105101520253035OUTPUT VOLTAGEvs. LOAD CURRENT FOR V+ AND V--2-4-6-88LOAD CURRENT (mA)O U T P U T V O L T A G E (V )64209.05.012345TRANSMITTER OUTPUT VOLTAGE (V+, V-)vs. LOAD CAPACITANCE AT DIFFERENT DATA RATES6.05.58.5LOAD CAPACITANCE (nF)V +, V (V )8.07.57.06.5MAX220–MAX249Drivers/ReceiversFigure 1. Transmitter Propagation-Delay Timing Figure 2. Receiver Propagation-Delay TimingFigure 3. Receiver-Output Enable and Disable Timing Figure 4. Transmitter-Output Disable TimingM A X 220–M A X 249Drivers/Receivers ENT ENR OPERATION STATUS TRANSMITTERSRECEIVERS00Normal Operation All Active All Active 01Normal Operation All Active All 3-State10Shutdown All 3-State All Low-Power Receive Mode 11ShutdownAll 3-StateAll 3-StateTable 1a. MAX245 Control Pin ConfigurationsENT ENR OPERATION STATUS TRANSMITTERS RECEIVERSTA1–TA4TB1–TB4RA1–RA5RB1–RB500Normal Operation All Active All Active All Active All Active 01Normal Operation All Active All Active RA1–RA4 3-State,RA5 Active RB1–RB4 3-State,RB5 Active 1ShutdownAll 3-StateAll 3-StateAll Low-Power Receive Mode All Low-Power Receive Mode 11Shutdown All 3-State All 3-StateRA1–RA4 3-State,RA5 Low-Power Receive ModeRB1–RB4 3-State,RB5 Low-Power Receive ModeTable 1b. MAX245 Control Pin ConfigurationsTable 1c. MAX246 Control Pin ConfigurationsENA ENB OPERATION STATUS TRANSMITTERS RECEIVERSTA1–TA4TB1–TB4RA1–RA5RB1–RB500Normal Operation All Active All Active All Active All Active 01Normal Operation All Active All 3-State All Active RB1–RB4 3-State,RB5 Active 1ShutdownAll 3-StateAll ActiveRA1–RA4 3-State,RA5 Active All Active 11Shutdown All 3-State All 3-StateRA1–RA4 3-State,RA5 Low-Power Receive ModeRB1–RB4 3-State,RA5 Low-Power Receive ModeMAX220–MAX249Drivers/ReceiversM A X 220–M A X 249_______________Detailed DescriptionThe MAX220–MAX249 contain four sections: dual charge-pump DC-DC voltage converters, RS-232 dri-vers, RS-232 receivers, and receiver and transmitter enable control inputs.Dual Charge-Pump Voltage ConverterThe MAX220–MAX249 have two internal charge-pumps that convert +5V to ±10V (unloaded) for RS-232 driver operation. The first converter uses capacitor C1 to dou-ble the +5V input to +10V on C3 at the V+ output. The second converter uses capacitor C2 to invert +10V to -10V on C4 at the V- output.A small amount of power may be drawn from the +10V (V+) and -10V (V-) outputs to power external circuitry (see the Typical Operating Characteristics section),except on the MAX225 and MAX245–MAX247, where these pins are not available. V+ and V- are not regulated,so the output voltage drops with increasing load current.Do not load V+ and V- to a point that violates the mini-mum ±5V EIA/TIA-232E driver output voltage when sourcing current from V+ and V- to external circuitry. When using the shutdown feature in the MAX222,MAX225, MAX230, MAX235, MAX236, MAX240,MAX241, and MAX245–MAX249, avoid using V+ and V-to power external circuitry. When these parts are shut down, V- falls to 0V, and V+ falls to +5V. For applica-tions where a +10V external supply is applied to the V+pin (instead of using the internal charge pump to gen-erate +10V), the C1 capacitor must not be installed and the SHDN pin must be tied to V CC . This is because V+is internally connected to V CC in shutdown mode.RS-232 DriversThe typical driver output voltage swing is ±8V when loaded with a nominal 5k ΩRS-232 receiver and V CC =+5V. Output swing is guaranteed to meet the EIA/TIA-232E and V.28 specification, which calls for ±5V mini-mum driver output levels under worst-case conditions.These include a minimum 3k Ωload, V CC = +4.5V, and maximum operating temperature. Unloaded driver out-put voltage ranges from (V+ -1.3V) to (V- +0.5V).Input thresholds are both TTL and CMOS compatible.The inputs of unused drivers can be left unconnected since 400k Ωinput pullup resistors to V CC are built in (except for the MAX220). The pullup resistors force the outputs of unused drivers low because all drivers invert.The internal input pullup resistors typically source 12µA,except in shutdown mode where the pullups are dis-abled. Driver outputs turn off and enter a high-imped-ance state—where leakage current is typically microamperes (maximum 25µA)—when in shutdownmode, in three-state mode, or when device power is removed. Outputs can be driven to ±15V. The power-supply current typically drops to 8µA in shutdown mode.The MAX220 does not have pullup resistors to force the outputs of the unused drivers low. Connect unused inputs to GND or V CC .The MAX239 has a receiver three-state control line, and the MAX223, MAX225, MAX235, MAX236, MAX240,and MAX241 have both a receiver three-state control line and a low-power shutdown control. Table 2 shows the effects of the shutdown control and receiver three-state control on the receiver outputs.The receiver TTL/CMOS outputs are in a high-imped-ance, three-state mode whenever the three-state enable line is high (for the MAX225/MAX235/MAX236/MAX239–MAX241), and are also high-impedance whenever the shutdown control line is high.When in low-power shutdown mode, the driver outputs are turned off and their leakage current is less than 1µA with the driver output pulled to ground. The driver output leakage remains less than 1µA, even if the transmitter output is backdriven between 0V and (V CC + 6V). Below -0.5V, the transmitter is diode clamped to ground with 1k Ωseries impedance. The transmitter is also zener clamped to approximately V CC + 6V, with a series impedance of 1k Ω.The driver output slew rate is limited to less than 30V/µs as required by the EIA/TIA-232E and V.28 specifica-tions. Typical slew rates are 24V/µs unloaded and 10V/µs loaded with 3Ωand 2500pF.RS-232 ReceiversEIA/TIA-232E and V.28 specifications define a voltage level greater than 3V as a logic 0, so all receivers invert.Input thresholds are set at 0.8V and 2.4V, so receivers respond to TTL level inputs as well as EIA/TIA-232E and V.28 levels.The receiver inputs withstand an input overvoltage up to ±25V and provide input terminating resistors withDrivers/ReceiversTable 2. Three-State Control of ReceiversMAX220–MAX249Drivers/Receiversnominal 5k Ωvalues. The receivers implement Type 1interpretation of the fault conditions of V.28 and EIA/TIA-232E.The receiver input hysteresis is typically 0.5V with a guaranteed minimum of 0.2V. This produces clear out-put transitions with slow-moving input signals, even with moderate amounts of noise and ringing. The receiver propagation delay is typically 600ns and is independent of input swing direction.Low-Power Receive ModeThe low-power receive mode feature of the MAX223,MAX242, and MAX245–MAX249 puts the IC into shut-down mode but still allows it to receive information. This is important for applications where systems are periodi-cally awakened to look for activity. Using low-power receive mode, the system can still receive a signal that will activate it on command and prepare it for communi-cation at faster data rates. This operation conserves system power.Negative Threshold—MAX243The MAX243 is pin compatible with the MAX232A, differ-ing only in that RS-232 cable fault protection is removed on one of the two receiver inputs. This means that control lines such as CTS and RTS can either be driven or left floating without interrupting communication. Different cables are not needed to interface with different pieces of equipment.The input threshold of the receiver without cable fault protection is -0.8V rather than +1.4V. Its output goes positive only if the input is connected to a control line that is actively driven negative. If not driven, it defaults to the 0 or “OK to send” state. Normally‚ the MAX243’s other receiver (+1.4V threshold) is used for the data line (TD or RD)‚ while the negative threshold receiver is con-nected to the control line (DTR‚ DTS‚ CTS‚ RTS, etc.). Other members of the RS-232 family implement the optional cable fault protection as specified by EIA/TIA-232E specifications. This means a receiver output goes high whenever its input is driven negative‚ left floating‚or shorted to ground. The high output tells the serial communications IC to stop sending data. To avoid this‚the control lines must either be driven or connected with jumpers to an appropriate positive voltage level.Shutdown—MAX222–MAX242On the MAX222‚ MAX235‚ MAX236‚ MAX240‚ and MAX241‚ all receivers are disabled during shutdown.On the MAX223 and MAX242‚ two receivers continue to operate in a reduced power mode when the chip is in shutdown. Under these conditions‚ the propagation delay increases to about 2.5µs for a high-to-low input transition. When in shutdown, the receiver acts as a CMOS inverter with no hysteresis. The MAX223 and MAX242 also have a receiver output enable input (EN for the MAX242 and EN for the MAX223) that allows receiver output control independent of SHDN (SHDN for MAX241). With all other devices‚ SHDN (SH DN for MAX241) also disables the receiver outputs.The MAX225 provides five transmitters and five receivers‚ while the MAX245 provides ten receivers and eight transmitters. Both devices have separate receiver and transmitter-enable controls. The charge pumps turn off and the devices shut down when a logic high is applied to the ENT input. In this state, the supply cur-rent drops to less than 25µA and the receivers continue to operate in a low-power receive mode. Driver outputs enter a high-impedance state (three-state mode). On the MAX225‚ all five receivers are controlled by the ENR input. On the MAX245‚ eight of the receiver out-puts are controlled by the ENR input‚ while the remain-ing two receivers (RA5 and RB5) are always active.RA1–RA4 and RB1–RB4 are put in a three-state mode when ENR is a logic high.Receiver and Transmitter EnableControl InputsThe MAX225 and MAX245–MAX249 feature transmitter and receiver enable controls.The receivers have three modes of operation: full-speed receive (normal active)‚ three-state (disabled)‚ and low-power receive (enabled receivers continue to function at lower data rates). The receiver enable inputs control the full-speed receive and three-state modes. The transmitters have two modes of operation: full-speed transmit (normal active) and three-state (disabled). The transmitter enable inputs also control the shutdown mode. The device enters shutdown mode when all transmitters are disabled. Enabled receivers function in the low-power receive mode when in shutdown.M A X 220–M A X 249Tables 1a–1d define the control states. The MAX244has no control pins and is not included in these tables. The MAX246 has ten receivers and eight drivers with two control pins, each controlling one side of the device. A logic high at the A-side control input (ENA )causes the four A-side receivers and drivers to go into a three-state mode. Similarly, the B-side control input (ENB ) causes the four B-side drivers and receivers to go into a three-state mode. As in the MAX245, one A-side and one B-side receiver (RA5 and RB5) remain active at all times. The entire device is put into shut-down mode when both the A and B sides are disabled (ENA = ENB = +5V).The MAX247 provides nine receivers and eight drivers with four control pins. The ENRA and ENRB receiver enable inputs each control four receiver outputs. The ENTA and ENTB transmitter enable inputs each control four drivers. The ninth receiver (RB5) is always active.The device enters shutdown mode with a logic high on both ENTA and ENTB .The MAX248 provides eight receivers and eight drivers with four control pins. The ENRA and ENRB receiver enable inputs each control four receiver outputs. The ENTA and ENTB transmitter enable inputs control four drivers each. This part does not have an always-active receiver. The device enters shutdown mode and trans-mitters go into a three-state mode with a logic high on both ENTA and ENTB .The MAX249 provides ten receivers and six drivers with four control pins. The ENRA and ENRB receiver enable inputs each control five receiver outputs. The ENTA and ENTB transmitter enable inputs control three dri-vers each. There is no always-active receiver. The device enters shutdown mode and transmitters go into a three-state mode with a logic high on both ENTA and ENTB . In shutdown mode, active receivers operate in a low-power receive mode at data rates up to 20kb/s.__________Applications InformationFigures 5 through 25 show pin configurations and typi-cal operating circuits. In applications that are sensitive to power-supply noise, V CC should be decoupled to ground with a capacitor of the same value as C1 and C2 connected as close as possible to the device.Drivers/Receivers。