MAX4761ETX+中文资料

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 .)。

General DescriptionThe MAX481E, MAX483E, MAX485E, MAX487E–MAX491E, and MAX1487E are low-power transceivers for RS-485 and RS-422 communications in harsh environ-ments. Each driver output and receiver input is protected against ±15kV electro-static discharge (ESD) shocks,without latchup. These parts contain one driver and one receiver. The MAX483E, MAX487E, MAX488E, and MAX489E feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly termi-nated cables, thus allowing error-free data transmission up to 250kbps. The driver slew rates of the MAX481E,MAX485E, MAX490E, MAX491E, and MAX1487E are not limited, allowing them to transmit up to 2.5Mbps.These transceivers draw as little as 120µA supply cur-rent when unloaded or when fully loaded with disabled drivers (see Selector Guide ). Additionally, the MAX481E,MAX483E, and MAX487E have a low-current shutdown mode in which they consume only 0.5µA. All parts oper-ate from a single +5V supply.Drivers are short-circuit current limited, and are protected against excessive power dissipation by thermal shutdown circuitry that places their outputs into a high-impedance state. The receiver input has a fail-safe feature that guar-antees a logic-high output if the input is open circuit.The MAX487E and MAX1487E feature quarter-unit-load receiver input impedance, allowing up to 128 trans-ceivers on the bus. The MAX488E–MAX491E are designed for full-duplex communications, while the MAX481E, MAX483E, MAX485E, MAX487E, and MAX1487E are designed for half-duplex applications.For applications that are not ESD sensitive see the pin-and function-compatible MAX481, MAX483, MAX485,MAX487–MAX491, and MAX1487.ApplicationsLow-Power RS-485 Transceivers Low-Power RS-422 Transceivers Level TranslatorsTransceivers for EMI-Sensitive Applications Industrial-Control Local Area NetworksNext-Generation Device Features♦For Fault-Tolerant Applications:MAX3430: ±80V Fault-Protected, Fail-Safe, 1/4-Unit Load, +3.3V, RS-485 TransceiverMAX3080–MAX3089: Fail-Safe, High-Speed (10Mbps), Slew-Rate-Limited, RS-485/RS-422Transceivers ♦For Space-Constrained Applications:MAX3460–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-422True Fail-Safe ReceiversMAX3030E–MAX3033E: ±15kV ESD-Protected,+3.3V, Quad RS-422 Transmitters ♦For Multiple Transceiver Applications:MAX3293/MAX3294/MAX3295: 20Mbps, +3.3V,SOT23, RS-485/RS-422 Transmitters ♦For Fail-Safe Applications:MAX3440E–MAX3444E: ±15kV ESD-Protected,±60V Fault-Protected, 10Mbps, Fail-Safe RS-485/J1708 Transceivers ♦For Low-Voltage Applications:MAX3483E/MAX3485E/MAX3486E/MAX3488E/MAX3490E/MAX3491E: +3.3V Powered, ±15kV ESD-Protected, 12Mbps, Slew-Rate-Limited, True RS-485/RS-422 TransceiversMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 Transceivers________________________________________________________________Maxim Integrated Products 1Ordering Information19-0410; Rev 4; 10/03For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at .Ordering Information continued at end of data sheet.Selector Guide appears at end of data sheet .M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers2_______________________________________________________________________________________Supply Voltage (V CC ) (12V)Control Input Voltage (–R —E –, DE)...................-0.5V to (V CC + 0.5V)Driver Input Voltage (DI).............................-0.5V to (V CC + 0.5V)Driver Output Voltage (Y, Z; 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)....727mW14-Pin Plastic DIP (derate 10.00mW/°C above +70°C)..800mW 8-Pin SO (derate 5.88mW/°C above +70°C).................471mW 14-Pin SO (derate 8.33mW/°C above +70°C)...............667mW Operating Temperature RangesMAX4_ _C_ _/MAX1487EC_ A.............................0°C to +70°C MAX4__E_ _/MAX1487EE_ A...........................-40°C to +85°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.ABSOLUTE MAXIMUM RATINGSPARAMETERSYMBOL MINTYPMAX UNITS Driver Common-Mode Output VoltageV OC 3V Change in Magnitude of Driver Differential Output Voltage for Complementary Output States ∆V OD 0.2V Change in Magnitude of Driver Common-Mode Output Voltage for Complementary Output States ∆V OD 0.2V Input High Voltage V IH 2.0V Input Low Voltage V IL 0.8V Input CurrentI IN1±2µADifferential Driver Output (no load)V OD15V 2V Differential Driver Output (with load)V OD2 1.551.0-0.8mA0.25mA -0.2Receiver Differential Threshold Voltage-0.20.2V Receiver Input Hysteresis ∆V TH 70mV Receiver Output High Voltage V OH 3.5Receiver Output Low Voltage V OL 0.4V Three-State (high impedance)Output Current at ReceiverI OZR±1µA 12k ΩCONDITIONSDE = 0V;V CC = 0V or 5.25V,all devices except MAX487E/MAX1487E R = 27Ωor 50Ω, Figure 8R = 27Ωor 50Ω, Figure 8R = 27Ωor 50Ω, Figure 8DE, DI, –R —E–MAX487E/MAX1487E,DE = 0V, V CC = 0V or 5.25VDE, DI, –R —E–DE, DI, –R —E–-7V ≤V CM ≤12V V CM = 0VI O = -4mA, V ID = 200mV I O = 4mA, V ID = -200mV R = 50Ω(RS-422)0.4V ≤V O ≤2.4VR = 27Ω(RS-485), Figure 8-7V ≤V CM ≤12V, all devices except MAX487E/MAX1487EReceiver Input Resistance R IN-7V ≤V CM ≤12V, MAX487E/MAX1487E48k ΩV TH I IN2Input Current (A, B)V IN = 12V V IN = -7V V IN = 12V V IN = -7VVMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 TransceiversSWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487EDC ELECTRICAL CHARACTERISTICS (continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers4_______________________________________________________________________________________SWITCHING CHARACTERISTICS—MAX483E, MAX487E/MAX488E/MAX489E(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)SWITCHING CHARACTERISTICS—MAX481E/MAX485E, MAX490E/MAX491E, MAX1487E(continued)(V CC = 5V ±5%, T A = T MIN to T MAX , unless otherwise noted.) (Notes 1, 2)2251000Figures 11 and 13, C L = 100pF, S2 closed Figures 11 and 13, C L = 100pF, S1 closed Figures 9 and 15, C L = 15pF, S2 closed,A - B = 2VCONDITIONSns 45100t ZH(SHDN)Driver Enable from Shutdown toOutput High (MAX481E)nsFigures 9 and 15, C L = 15pF, S1 closed,B - A = 2Vt ZL(SHDN)Receiver Enable from Shutdownto Output Low (MAX481E)ns 45100t ZL(SHDN)Driver Enable from Shutdown toOutput Low (MAX481E)ns 2251000t ZH(SHDN)Receiver Enable from Shutdownto Output High (MAX481E)UNITS MINTYP MAX SYMBOLPARAMETERt PLH t SKEW Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pFt PHL Figures 10 and 12, R DIFF = 54Ω,C L1= C L2= 100pFDriver Input to Output Driver Output Skew to Output ns 20800ns ns 2000MAX483E/MAX487E, Figures 11 and 13,C L = 100pF, S2 closedt ZH(SHDN)Driver Enable from Shutdown to Output High2502000ns2500MAX483E/MAX487E, Figures 9 and 15,C L = 15pF, S1 closedt ZL(SHDN)Receiver Enable from Shutdown to Output Lowns 2500MAX483E/MAX487E, Figures 9 and 15,C L = 15pF, S2 closedt ZH(SHDN)Receiver Enable from Shutdown to Output Highns 2000MAX483E/MAX487E, Figures 11 and 13,C L = 100pF, S1 closedt ZL(SHDN)Driver Enable from Shutdown to Output Lowns 50200600MAX483E/MAX487E (Note 5)t SHDN Time to Shutdownt PHL t PLH , t PHL < 50% of data period Figures 9 and 15, C RL = 15pF, S2 closed Figures 9 and 15, C RL = 15pF, S1 closed Figures 9 and 15, C RL = 15pF, S2 closed Figures 9 and 15, C RL = 15pF, S1 closed Figures 11 and 13, C L = 15pF, S2 closed Figures 10 and 14, R DIFF = 54Ω,C L1= C L2= 100pFFigures 11 and 13, C L = 15pF, S1 closed Figures 11 and 13, C L = 100pF, S1 closed Figures 11 and 13, C L = 100pF, S2 closed CONDITIONSkbps 250f MAX 2508002000Maximum Data Rate ns 2550t HZ Receiver Disable Time from High ns 25080020002550t LZ Receiver Disable Time from Low ns 2550t ZH Receiver Enable to Output High ns 2550t 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 10 and 14, 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 10 and 12, 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 PARAMETERMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers_______________________________________________________________________________________505101520253035404550OUTPUT CURRENT vs.RECEIVER OUTPUT LOW VOLTAGEM A X 481E -01OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )1.52.02.51.00.50.10.20.30.40.50.60.70.80.9-60-2060RECEIVER OUTPUT LOW VOLTAGEvs. TEMPERATURETEMPERATURE (°C)O U T P U T L O W V O L T A G E (V )20100-4040800-5-10-15-20-251.53.0OUTPUT CURRENT vs.RECEIVER OUTPUT HIGH VOLTAGEM A X 481E -02OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )5.04.54.02.02.53.53.03.23.43.63.84.04.24.44.64.8-60-2060RECEIVER OUTPUT HIGH VOLTAGEvs. TEMPERATURETEMPERATURE (°C)O U T P U T H I G H V O L T A G E (V )20100-4040800102030405060708090DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGEM A X 481E -05DIFFERENTIAL OUTPUT VOLTAGE (V)O U T P U T C U R R E N T (m A )1.52.0 2.53.0 3.54.0 4.51.00.50__________________________________________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 MAX481E/MAX483E/MAX487E are put into shutdown by bringing –R —E –high and DE low. If the inputs are in this state forless than 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 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers6___________________________________________________________________________________________________________________Typical Operating Characteristics (continued)(V CC = 5V, T A = +25°C, unless otherwise noted.)1.52.32.22.12.01.91.81.71.6-60-2060DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURETEMPERATURE (°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 )20100-404080020406080100120140OUTPUT CURRENT vs. DRIVER OUTPUT LOW VOLTAGEM A X 481E -07OUTPUT LOW VOLTAGE (V)O U T P U T C U R R E N T (m A )246810120-10-20-30-40-50-60-70-80-90-100-8-2OUTPUT CURRENT vs. DRIVER OUTPUT HIGH VOLTAGEM A X 481E -08OUTPUT HIGH VOLTAGE (V)O U T P U T C U R R E N T (m A )642-6-400100200300400500600-60-2060MAX481E/MAX485E/MAX490E/MAX491E SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20100-4040800100200300400500600-60-2060MAX483E/MAX487E–MAX489E SUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20100-404080100200300400500600-60-2060MAX1487ESUPPLY CURRENT vs. TEMPERATURETEMPERATURE (°C)S U P P L Y C U R R E N T (µA )20100-404080±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 Transceivers_______________________________________________________________________________________7MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E______________________________________________________________Pin DescriptionM A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers8_________________________________________________________________________________________________Function Tables (MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E) Table 1. Transmitting__________Applications Information The MAX481E/MAX483E/MAX485E/MAX487E–MAX491E and MAX1487E are low-power transceivers for RS-485 and RS-422 communications. These “E” versions of the MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 provide extra protection against ESD. The rugged MAX481E, MAX483E, MAX485E, MAX497E–MAX491E, and MAX1487E are intended for harsh envi-ronments where high-speed communication is important. These devices eliminate the need for transient suppres-sor diodes and the associated high capacitance loading. The standard (non-“E”) MAX481, MAX483, MAX485, MAX487–MAX491, and MAX1487 are recommended for applications where cost is critical.The MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E can transmit and receive at data rates up to 2.5Mbps, while the MAX483E, MAX487E, MAX488E, and MAX489E are specified for data rates up to 250kbps. The MAX488E–MAX491E are full-duplex transceivers, while the MAX481E, MAX483E, MAX487E, and MAX1487E are half-duplex. In addition, driver-enable (DE) and receiver-enable (RE) pins are included on the MAX481E, MAX483E, MAX485E, MAX487E, MAX489E, MAX491E, and MAX1487E. When disabled, the driver and receiver outputs are high impedance.±15kV ESD Protection As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against electro-static discharges encountered during handling and assembly. The driver outputs and receiver inputs have extra protection against static electricity. Maxim’s engi-neers developed state-of-the-art structures to protect 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 MAX481E, MAX483E, MAX485E, MAX487E–MAX491E, and MAX1487E keep working without latchup.ESD protection can be tested in various ways; the transmitter outputs and receiver inputs of this product family are characterized for protection to ±15kV using the Human Body Model.Other ESD test methodologies include IEC10004-2 con-tact discharge and IEC1000-4-2 air-gap discharge (for-merly IEC801-2).ESD Test Conditions ESD performance depends on a variety of conditions. Contact Maxim for a reliability report that documents test set-up, test methodology, and test results.Human Body Model Figure 4 shows the Human Body Model, and Figure 5 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 1.5kΩresistor.IEC1000-4-2 The IEC1000-4-2 standard covers ESD testing and per-formance of finished equipment; it does not specifically refer to integrated circuits (Figure 6).MAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers_______________________________________________________________________________________9M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers10______________________________________________________________________________________Figure 8. Driver DC Test LoadFigure 9. Receiver Timing Test LoadMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers______________________________________________________________________________________11Figure 10. Driver/Receiver Timing Test Circuit Figure 11. Driver Timing Test LoadFigure 12. Driver Propagation DelaysFigure 13. Driver Enable and Disable Times (except MAX488E and MAX490E)Figure 14. Receiver Propagation DelaysFigure 15. Receiver Enable and Disable Times (except MAX488E and MAX490E)M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers12______________________________________________________________________________________The major difference between tests done using the Human Body Model and IEC1000-4-2 is higher peak current in IEC1000-4-2, because series resistance is lower in the IEC1000-4-2 model. Hence, the ESD with-stand voltage measured to IEC1000-4-2 is generally lower than that measured using the Human Body Model. Figure 7 shows the current waveform for the 8kV IEC1000-4-2 ESD contact-discharge test.The air-gap test involves approaching the device with a charged probe. The contact-discharge 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. Of course, all pins require this protec-tion during manufacturing—not just inputs and outputs.Therefore,after PC board assembly,the Machine Model is less relevant to I/O ports.MAX487E/MAX1487E:128 Transceivers on the BusThe 48k Ω, 1/4-unit-load receiver input impedance of the MAX487E and MAX1487E allows up to 128 transceivers on a bus, compared to the 1-unit load (12k Ωinput impedance) of standard RS-485 drivers (32 transceivers maximum). Any combination of MAX487E/MAX1487E and other RS-485 transceivers with a total of 32 unit loads or less can be put on the bus. The MAX481E,MAX483E, MAX485E, and MAX488E–MAX491E have standard 12k Ωreceiver input impedance.MAX483E/MAX487E/MAX488E/MAX489E:Reduced EMI and Reflections The MAX483E and MAX487E–MAX489E are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 16shows the driver output waveform and its Fourier analy-sis of a 150kHz signal transmitted by a MAX481E,MAX485E, MAX490E, MAX491E, or MAX1487E. High-frequency harmonics with large amplitudes are evident.Figure 17 shows the same information displayed for a MAX483E, MAX487E, MAX488E, or MAX489E transmit-ting under the same conditions. Figure 17’s high-fre-quency harmonics have much lower amplitudes, and the potential for EMI is significantly reduced.Low-Power Shutdown Mode (MAX481E/MAX483E/MAX487E)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 0.5µA 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 MAX481E, MAX483E, and MAX487E, the t ZH and t ZL enable times assume the part was not in the low-power shutdown state (the MAX485E, MAX488E–MAX491E, and MAX1487E can not be shut down). The t ZH(SHDN)and t ZL(SHDN)enable times assume the parts were shut down (see Electrical Characteristics ).500kHz/div0Hz5MHz 10dB/div Figure 16. Driver Output Waveform and FFT Plot ofMAX485E/MAX490E/MAX491E/MAX1487E Transmitting a 150kHz Signal500kHz/div0Hz5MHz10dB/divFigure 17. Driver Output Waveform and FFT Plot ofMAX483E/MAX487E–MAX489E Transmitting a 150kHz SignalIt 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 RE, DE inputs equal a logical 0,1 or 1,1 or 0, 0.)Driver Output Protection Excessive 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 circuits over the whole common-mode voltage range (see Typical Operating Characteristics). In addition, a thermal shut-down circuit forces the driver outputs into a high-imped-ance state if the die temperature rises excessively.Propagation Delay Many digital encoding schemes depend on the differ-ence between the driver and receiver propagation delay times. Typical propagation delays are shown in Figures 19–22 using Figure 18’s test circuit.The difference in receiver delay times, t PLH- t PHL, is typically under 13ns for the MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E, and is typically less than 100ns for the MAX483E and MAX487E–MAX489E.The driver skew times are typically 5ns (10ns max) for the MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E, and are typically 100ns (800ns max) for the MAX483E and MAX487E–MAX489E.Typical Applications The MAX481E, MAX483E, MAX485E, MAX487E–MAX491E, and MAX1487E transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figures 25 and 26 show typical net-work application circuits. These parts can also be used as line repeaters, with cable lengths longer than 4000 feet. 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 MAX483E and MAX487E–MAX489E are more tolerant of imperfect termination. Bypass the V CC pin with 0.1µF.Isolated RS-485 For isolated RS-485 applications, see the MAX253 and MAX1480 data sheets.Line Length vs. Data Rate The RS-485/RS-422 standard covers line lengths up to 4000 feet. Figures 23 and 24 show the system differen-tial voltage for the parts driving 4000 feet of 26AWG twisted-pair wire at 110kHz into 100Ωloads.Figure 18. Receiver Propagation Delay Test CircuitMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers ______________________________________________________________________________________13M A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers14______________________________________________________________________________________25ns/div 5V/divRO B A500mV/div Figure 19. MAX481E/MAX485E/MAX490E/MAX1487E Receiver t PHL25ns/div5V/div ROBA500mV/divFigure 20. MAX481E/MAX485E/MAX490E/MAX491E/MAX1487E Receiver t PLH200ns/div 5V/divRO B A500mV/div Figure 21. MAX483E/MAX487E–MAX489E Receiver t PHL200ns/div5V/div ROBA500mV/divFigure 22. MAX483E/MAX487E–MAX489E Receiver t PLH2µs/div DO 0V0V5V5V -1V 0DIV A - V BFigure 23. MAX481E/MAX485E/MAX490E/MAX491E/MAX1487E System Differential Voltage at 110kHz Driving 4000ft of Cable 2µs/divDO0V0V 5V 5V -1V1V0DIV B - V AFigure 24. MAX483E/MAX1487E–MAX489E System Differential Voltage at 110kHz Driving 4000ft of CableMAX481E/MAX483E/MAX485E/MAX487E–MAX491E/MAX1487E±15kV ESD-Protected, Slew-Rate-Limited,Low-Power, RS-485/RS-422 Transceivers______________________________________________________________________________________15Figure 26. MAX488E–MAX491E Full-Duplex RS-485 NetworkFigure 25. MAX481E/MAX483E/MAX485E/MAX487E/MAX1487E Typical Half-Duplex RS-485 NetworkM A X 481E /M A X 483E /M A X 485E /M A X 487E –M A X 491E /M A X 1487E±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 Transceivers 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©2003 Maxim Integrated ProductsPrinted USAis a registered trademark of Maxim Integrated Products.Package InformationFor the latest package outline information, go to /packages .Ordering Information (continued)Selector GuideChip InformationTRANSISTOR COUNT: 295。

General DescriptionThe MAX3230E/AE and MAX3231E/AE are +2.5V to +5.5V powered EIA/TIA-232 and V.28/V.24 communica-tions interfaces with low power requirements, high data-rate capabilities, and enhanced electrostatic discharge (ESD) protection, in a chip-scale package (UCSP™)and WLP package. All transmitter outputs and receiver inputs are protected to ±15kV using IEC 1000-4-2 Air-Gap Discharge, ±8kV using I EC 1000-4-2 Contact Discharge, and ±15kV using the Human Body Model.The MAX3230E/AE and MAX3231E/AE achieve a 1µA supply current with Maxim’s AutoShutdown™ feature.They save power without changing the existing BIOS or operating systems by entering low-power shutdown mode when the RS-232 cable is disconnected, or when the transmitters of the connected peripherals are off.The transceivers have a proprietary low-dropout trans-mitter output stage, delivering RS-232-compliant perfor-mance from a +3.1V to +5.5V supply, and RS-232-compatible performance with a supply voltage as low as +2.5V. The dual charge pump requires only four,small 0.1µF capacitors for operation from a +3.0V sup-ply. Each device is guaranteed to run at data rates of 250kbps while maintaining RS-232 output levels.The MAX3230E/AE and MAX3231E/AE offer a separate power-supply input for the logic interface, allowing con-figurable logic levels on the receiver outputs and trans-mitter inputs. Operating over a +1.65V to V CC range, V L provides the MAX3230E/AE and MAX3231E/AE com-patibility with multiple logic families.The MAX3231E/AE contains one receiver and one trans-mitter. The MAX3230E/AE contains two receivers and two transmitters. The MAX3230E/AE and MAX3231E/AE are available in tiny chip-scale and WLP packaging and are specified across the extended industrial (-40°C to +85°C)temperature range.ApplicationsPersonal Digital Assistants Cell-Phone Data Lump Cables Set-Top Boxes Handheld Devices Cell PhonesFeatures♦6 x 5 Chip-Scale Package (UCSP) and WLP Package♦ESD Protection for RS-232 I/O Pins±15kV—IEC 1000-4-2 Air-Gap Discharge ±8kV—IEC 1000-4-2 Contact Discharge ±15kV—Human Body Model ♦1µA Low-Power AutoShutdown ♦250kbps Guaranteed Data Rate♦Meet EIA/TIA-232 Specifications Down to +3.1V ♦RS-232 Compatible to +2.5V Allows Operation from Single Li+ Cell ♦Small 0.1µF Capacitors ♦Configurable Logic LevelsMAX3230E/MAX3230AE/MAX3231E/MAX3231AE±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP________________________________________________________________Maxim Integrated Products 1Typical Operating Circuits19-3250; Rev 1; 10/08For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,or visit Maxim’s website at .Ordering InformationUCSP is a trademark of Maxim Integrated Products, Inc.AutoShutdown is a trademark of Maxim Integrated Products, Inc.Typical Operating Circuits continued at end of data sheet.Pin Configurations appear at end of data sheet.+Denotes a lead-free/RoHS-compliant package.T = Tape-and-reel.M A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A E±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 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.V CC to GND...........................................................-0.3V to +6.0V V+ to GND.............................................................-0.3V to +7.0V V- to GND..............................................................+0.3V to -7.0V V+ to |V-| (Note 1)................................................................+13V V L to GND..............................................................-0.3V to +6.0V Input VoltagesT_IN_, FORCEON, FORCEOFF to GND.....-0.3V to (V L + 0.3V)R_IN_ to GND ...................................................................±25V Output VoltagesT _OUT to GND...............................................................±13.2V R _OUT INVALID to GND............................-0.3V to (V L + 0.3V)INVALID to GND.........................................-0.3V to (V CC + 0.3V)Short-Circuit Duration T _OUT to GND........................Continuous Continuous Power Dissipation (T A = +70°C)6 ✕5 UCSP (derate 10.1mW/°C above +70°C)...........805mW 6 ✕5 WLP (derate 20mW/°C above +70°C).....................1.6W Operating Temperature Range ...........................-40°C to +85°C Junction Temperature......................................................+150°C Storage Temperature Range.............................-65°C to +150°C Bump Temperature (soldering)Infrared (15s)...............................................................+200°C Vapor Phase (20s).......................................................+215°CELECTRICAL CHARACTERISTICSNote 1:V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.MAX3230E/MAX3230AE/MAX3231E/MAX3231AEELECTRICAL CHARACTERISTICS (continued)(V CC = +2.5V to +5.5V, V L = +1.65V to +5.5V, C1–C4 = 0.1µF, tested at +3.3V ±10%, T A = T MIN to T MAX . Typical values are at T A =+25°C, unless otherwise noted.) (Note 2)±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLPM A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A E±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 4_______________________________________________________________________________________TIMING CHARACTERISTICSTypical 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.)-6-2-4204615002000500100025003000TRANSMITTER 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 )10520152530025003000SLEW RATE vs. LOAD CAPACITANCELOAD CAPACITANCE (pF)S L E W R A T E (V /μs )1000500150020000642810121416182010005001500200025003000OPERATING SUPPLY CURRENT vs. LOAD CAPACITANCE (MAX3231E)LOAD CAPACITANCE (pF)O P E R A T I N G S U P P L Y C U R R E N T (m A )MAX3230E/MAX3230AE/MAX3231E/MAX3231AE±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP_______________________________________________________________________________________5Typical 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.)064281012141618202.53.53.04.04.55.05.5OPERATING SUPPLY CURRENT vs. SUPPLY VOLTAGE (MAX3231E)M A X 3230E /30A E /31E /31A E t o c 04SUPPLY VOLTAGE (V)O P E R A T I N G S U P P L Y C U R R E N T (m A )-8-4-620-2864102.53.53.04.04.55.05.5TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (V CC RISING)SUPPLY 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 )-8-4-620-2864102.53.53.04.0 4.55.0 5.5TRANSMITTER OUTPUT VOLTAGE vs. SUPPLY VOLTAGE (V CC FALLING)SUPPLY 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 )M A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A E±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 6_______________________________________________________________________________________Detailed DescriptionDual Mode™ Regulated Charge-PumpVoltage ConverterThe MAX3230E/AE and MAX3231E/AE internal power supply consists of a dual-mode regulated charge pump. For supply voltages above +3.7V, the charge pump generates +5.5V at V+ and -5.5V at V-. The charge pumps operate in a discontinuous mode. If the output voltages are less than ±5.5V, the charge pumps are enabled. I f the output voltages exceed ±5.5V, the charge pumps are disabled.For supply voltages below +2.85V, the charge pump generates +4.0V at V+ and -4.0V at V-. The charge pumps operate in a discontinuous mode. I f the output voltages are less than ±4.0V, the charge pumps are enabled. I f the output voltages exceed ±4.0V, the charge pumps are disabled.Each charge pump requires a flying capacitor (C1, C2)and a reservoir capacitor (C3, C4) to generate the V+and V- supply voltages.Voltage Generation in theSwitchover RegionThe MAX3230E/AE and MAX3231E/AE include a switchover circuit between these two modes that have approximately 400mV of hysteresis around the switchover point. The hysteresis is shown in Figure 1.This large hysteresis eliminates mode changes due to power-supply bounce.For example, a three-cell NiMh battery system starts at V CC = +3.6V, and the charge pump generates an out-put voltage of ±5.5V. As the battery discharges, the MAX3230E/AE and MAX3231E/AE maintain the outputsThe output regulation points then change to ±4.0V.When V CC is rising, the charge pump generates an out-put voltage of ±4.0V, while V CC is between +2.5V and +3.5V. When V CC rises above the switchover voltage of +3.5V, the charge pump switches modes to generate an output of ±5.5V.Table 1 shows different supply schemes and their oper-ating voltage ranges.RS-232 TransmittersThe transmitters are inverting level translators that convert CMOS logic levels to RS-232 levels. The MAX3230E/AE and MAX3231E/AE automatically reduce the RS-232-compliant levels (±5.5V) to RS-232-compat-ible levels (±4.0V) when V CC falls below approximately +3.1V. The reduced levels also reduce supply-current requirements, extending battery life. Built-in hysteresis of approximately 400mV for V CC ensures that the RS-Figure 1. V+ Switchover for Changing V CC6V4V20ms/divV CCV+Dual Mode is a trademark of Maxim Integrated Products, Inc.MAX3230E/MAX3230AE/MAX3231E/MAX3231AE232 output levels do not change if V CC is noisy or has a sudden current draw causing the supply voltage to drop slightly. The outputs return to RS-232-compliant levels (±5.5V) when V CC rises above approximately +3.5V.The MAX3230E/AE and MAX3231E/AE transmitters guarantee a 250kbps data rate with worst-case loads of 3k Ωin parallel with 1000pF.When FORCEOFF is driven to ground, the transmitters and receivers are disabled and the outputs become high impedance. When the AutoShutdown circuitry senses that all receiver and transmitter inputs are inac-tive for more than 30µs, the transmitters are disabled and the outputs go to a high-impedance state. When the power is off, the MAX3230E/AE and MAX3231E/AE permit the transmitter outputs to be driven up to ±12V.The transmitter inputs do not have pullup resistors.Connect unused inputs to GND or V L .RS-232 ReceiversThe MAX3230E/AE and MAX3231E/AE receivers con-vert RS-232 signals to logic-output levels. All receivers have inverting tri-state outputs and can be active or inactive. I n shutdown (FORCEOFF = low) or in AutoShutdown, the MAX3230E/AE and MAX3231E/AE receivers are in a high-impedance state (Table 2).The MAX3230E/AE and MAX3231E/AE feature an INVALID output that is enabled low when no valid RS-232signal levels have been detected on any receiver inputs.INVALID is functional in any mode (Figures 2 and 3).AutoShutdownThe MAX3230E/AE and MAX3231E/AE achieve a 1µA supply current with Maxim’s AutoShutdown feature,which operates when FORCEON is low and FORCEOFF is high. When these devices sense no valid signal lev-els on all receiver inputs for 30µs, the on-board charge pump and drivers are shut off, reducing V CC supply current to 1µA. This occurs if the RS-232 cable is dis-connected or the connected peripheral transmitters are turned off. The device turns on again when a valid level is applied to any RS-232 receiver input. As a result, the system saves power without changes to the existing BIOS or operating system.Table 2 and Figure 2c summarize the MAX3230E/AE and MAX3231E/AE operating modes. FORCEON and FORCEOFF override AutoShutdown. When neither con-trol is asserted, the I C selects between these states automatically, based on receiver input levels. Figures 2a, 2b, and 3a depict valid and invalid RS-232-receiver levels. Figures 3a and 3b show the input levels and tim-ing diagram for AutoShutdown operation.A system with AutoShutdown can require time to wake up. Figure 4 shows a circuit that forces the transmitters on for 100ms, allowing enough time for the other system to realize that the MAX3230E/AE and±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP_______________________________________________________________________________________7MAX3231E/AE are active. If the other system transmits valid RS-232 signals within that time, the RS-232 ports on both systems remain enabled.When shut down, the device’s charge pumps are off,V+ is pulled to V CC , V- is pulled to ground, and the transmitter outputs are high impedance. The time required to exit shutdown is typically 100µs (Figure 3b).V L Logic Supply InputUnlike other RS-232 interface devices, where the receiv-er outputs swing between 0 and V CC , the MAX3230E/AE and MAX3231E/AE feature a separate logic supply input (V L ) that sets V OH for the receiver outputs. The transmit-ter inputs (T_IN), FORCEON, and FORCEOFF , are also referred to V L . This feature allows maximum flexibility in interfacing to different systems and logic levels.Connect V L to the system’s logic supply voltage (+1.65V to +5.5V), and bypass it with a 0.1µF capacitor to GND.I f the logic supply is the same as V CC , connect V L to V CC . Always enable V CC before enabling the V L supply.V CC must be greater than or equal to the V L supply.Software-Controlled ShutdownIf direct software control is desired, connect FORCEOFF and FORCEON together to disable AutoShutdown. Themicrocontroller (µC) then drives FORCEOFF and FORCEON like a SHDN input. INVALID can be used to alert the µC to indicate serial data activity.±15kV ESD ProtectionAs with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against electro-static discharges encountered during handling and assembly. The driver outputs and receiver inputs of the MAX3230E/AE and MAX3231E/AE have extra protec-tion against static electricity. Maxim’s engineers have developed state-of-the-art structures to protect these pins against ESD of ±15kV without damage. The ESD structures withstand high ESD in all states: normal operation, shutdown, and power-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.ESD protection can be tested in various ways; the trans-mitter outputs and receiver inputs of this product family are characterized for protection to the following limits:1) ±15kV using the Human Body Model2) ±8kV using the Contact Discharge method specified in IEC 1000-4-23) ±15kV using the IEC 1000-4-2 Air-Gap methodESD 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 5a shows the Human Body Model. Figure 5b 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 interest,M A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A E±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 8_______________________________________________________________________________________Figure 2a. MAX323_E Entering 1µA Supply Mode with AutoShutdownFigure 2b. MAX323_E with Transmitters Enabled UsingAutoShutdownFigure 2c. MAX323_E AutoShutdown LogicMAX3230E/MAX3230AE/MAX3231E/MAX3231AEwhich 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 ICs. The MAX3230E/AE and MAX3231E/AE aid in designing equipment that meets Level 4 (the highest level) of I EC 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 a higher peak current in I EC 1000-4-2, because series resistance is lower in the IEC 1000-4-2 model. Hence, the ESD with-stands voltage measured to IEC 1000-4-2 and is gener-ally lower than that measured using the Human Body Model. Figure 6a shows the I EC 1000-4-2 model, and Figure 6b shows the current waveform for the ±8kV IEC 1000-4-2 Level 4 ESD Contact Discharge test.The Air-Gap test involves approaching the device with a charged probe. The Contact Discharge 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 resistance. I ts objective is to emulate the stress caused by contact that occurs with handling and assembly during manufactur-ing. Of course, 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; either polarized or nonpolarized capacitors can be used. However, ceramic chip capaci-tors with an X7R or X5R dielectric work best. The charge pump requires 0.1µF capacitors for 3.3V operation. For other supply voltages, see Table 3 for required capaci-tor values. Do not use values smaller than those listed in Table 3. Increasing the capacitor values (e.g., by a fac-tor of 2) reduces ripple on the transmitter outputs and slightly reduces power consumption. C2, C3, and C4can be increased without changing the vaue of C1.Caution: Do not increase C1 without also increasing the values of C2, C3, and C4 to maintain the proper ratios (C1 to the other capacitors).When using the minimum required capacitor values,make sure the capacitor value does not degrade exces-sively with temperature. If in doubt, use capacitors with±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP_______________________________________________________________________________________9Figure 3. AutoShutdown Trip LevelsFigure 4. AutoShutdown with Initial Turn-On to Wake Up aMouse or Another SystemM A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A Ea larger nominal value. The capacitor’s equivalent series resistance (ESR) usually rises at low temperatures and 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 the charge-pump capacitor C1. Connect bypass capaci-tors as close to the IC as possible.Transmitter Outputs whenExiting ShutdownFigure 7 shows a transmitter output when exiting shut-down mode. The transmitter is loaded with 3k Ωin par-allel with 1000pF. The transmitter output displays no ringing or undesirable transients as it comes out of shutdown, and is enabled only when the magnitude of V- exceeds approximately -3V.High Data RatesThe MAX3230E/AE and MAX3231E/AE maintain the RS-232 ±5.0V minimum transmitter output voltage even at high data rates. Figure 8 shows a transmitter loop-back test circuit. Figure 9 shows a loopback test result at 120kbps, and Figure 10 shows the same test at 250kbps. For Figure 9, the transmitter was driven at 120kbps into an RS-232 load in parallel with 1000pF.For Figure 10, a single transmitter was driven at 250kbps and loaded with an RS-232 receiver in paral-lel with 1000pF.Figure 6a. IEC 1000-4-2 ESD Test ModelFigure 6b. IEC 1000-4-2 ESD Generator Current Waveform±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 10______________________________________________________________________________________Figure 5a. Human Body ESD Test ModelsFigure 5b. Human Body Model Current WaveformMAX3230E/MAX3230AE/MAX3231E/MAX3231AEUCSP Applications InformationFor the latest application details on UCSP construction,dimensions, tape carrier information, PC board tech-niques, bump-pad layout, and recommended reflow temperature profile, as well as the latest information on reliability testing results, refer to the Application Note UCSP—A Wafer-Level Chip-Scale Package available on Maxim’s website at /ucsp .Chip InformationTRANSISTOR COUNT:698PROCESS: CMOSFigure 8. Transmitter Loopback Test CircuitR_OUTT_OUTT_IN-5V5V 05V5V 04μs/divFigure 10. Loopback Test Result at 250kbps-5V 5V05V5V0R_OUTT_OUTT_IN4μs/divFigure 7. Transmitter Outputs Exiting Shutdown or Powering Up FORCEON =FORCEOFFT_OUT4μs/div2V/div5V/div±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP______________________________________________________________________________________11M A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A E±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 12______________________________________________________________________________________MAX3230E/MAX3230AE/MAX3231E/MAX3231AEPin Configurations±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP______________________________________________________________________________________13M A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A E±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 14______________________________________________________________________________________Pin Configurations (continued)MAX3230E/MAX3230AE/MAX3231E/MAX3231AE±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP______________________________________________________________________________________15Package InformationFor the latest package outline information and land patterns, go to /packages .M A X 3230E /M A X 3230A E /M A X 3231E /M A X 3231A E±15kV ESD-Protected +2.5V to +5.5V RS-232 Transceivers in UCSP and WLP 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©2008 Maxim Integrated Productsis a registered trademark of Maxim Integrated Products, Inc.。