MAX4666EPE中文资料

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 .)。

LM4666Filterless High Efficiency Stereo 1.2W Switching Audio AmplifierGeneral DescriptionThe LM4666is a fully integrated single-supply high efficiency switching audio amplifier.It features an innovative modulator that eliminates the LC output filter used with typical switching amplifiers.Eliminating the output filter reduces parts count,simplifies circuit design,and reduces board area.The LM4666processes analog inputs with a delta-sigma modu-lation technique that lowers output noise and THD when compared to conventional pulse width modulators.The LM4666is designed to meet the demands of mobile phones and other portable communication devices.Operat-ing on a single 3V supply,it is capable of driving 8Ωtrans-ducer loads at a continuous average output of 450mW with less than 1%THD+N.Its flexible power supply requirements allow operation from 2.8V to 5.5V.The LM4666has high efficiency with an 8Ωtransducer load compared to a typical Class AB amplifier.With a 3V supply,the IC’s efficiency for a 100mW power level is 79%,reaching 84%at 450mW output power.The LM4666features a low-power consumption shutdown mode.Shutdown may be enabled by driving the Shutdown pin to a logic low (GND).The LM4666has fixed selectable gain of either 6dB or 12dB.The LM4666has short circuit protection against a short from the outputs to V DD or GND.Key Specificationsj Efficiency at 3V,100mW into 8Ωtransducer 79%(typ)j Efficiency at 3V,450mW into 8Ωtransducer 84%(typ)j Efficiency at 5V,1W into 8Ωtransducer 85%(typ)j Total quiescent power supply current 7.0mA (typ)j Total shutdown power supply current 0.02µA (typ)j Single supply range2.8V to 5.5VFeaturesn No output filter required for inductive transducers n Selectable gain of 6dB or 12dB n Very fast turn on time:6ms (typ)n Minimum external componentsn "Click and pop"suppression circuitry n Micro-power shutdown mode n Short circuit protectionnAvailable in space-saving SDA packageApplicationsn Mobile phones n PDAsn Portable electronic devicesTypical ApplicationBoomer ®is a registered trademark of National Semiconductor Corporation.200558E6FIGURE 1.Typical Audio Amplifier Application CircuitMay 2004LM4666Filterless High Efficiency Stereo 1.2W Switching Audio Amplifier©2004National Semiconductor Corporation Connection DiagramsSDA Package200558I8Top ViewOrder Number LM4666SDA See NS Package Number SDA14ASDA Marking200558I9Top View Z —Plant Code XY —Date Code TT —Die Traceability L4666—LM4666L M 4666 2Absolute Maximum Ratings(Notes1,2) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.Supply Voltage(Note1) 6.0V Storage Temperature−65˚C to+150˚C Voltage at Any Input Pin V DD+0.3V≥V≥GND-0.3V Power Dissipation(Note3)Internally Limited ESD Susceptibility,pins4,7,11,14(Note4)1kV ESD Susceptibility,all other pins(Note4)2.0kV ESD Susceptibility(Note5)200VJunction Temperature(T J)150˚C Thermal ResistanceθJA(SDA)63˚C/W θJC(SDA)12˚C/W Soldering InformationSee AN-1112"microSMD Wafers Level Chip Scale Package."Operating Ratings(Notes1,2)Temperature RangeT MIN≤T A≤T MAX−40˚C≤T A≤85˚C Supply Voltage 2.8V≤V DD≤5.5VElectrical Characteristics VDD =5V(Notes1,2)The following specifications apply for V DD=5V and R L=15µH+8Ω+15µH unless otherwise specified.Limits apply for T A= 25˚C.Symbol Parameter ConditionsLM4666Units(Limits) Typical Limit(Note6)(Notes7,8)I DD Quiescent Power Supply Current V IN=0V,No LoadV IN=0V,R L=15µH+8Ω+15µH 1516mAmAI SD Shutdown Current V SD=GND(Note9)0.02µA V SDIH Shutdown Voltage Input High 1.2V V SDIL Shutdown Voltage Input Low 1.1V V GSIH Gain Select Input High 1.2V V GSIL Gain Select Input Low 1.1V A V Closed Loop Gain V Gain Select=V DD6dB A V Closed Loop Gain V Gain Select=GND12dB V OS Output Offset Voltage10mV T WU Wake-up Time6msP o Output Power THD=1%(max),f=1kHz,22kHz BW1.2WTHD+N Total Harmonic Distortion+Noise P O=100mW RMS/Channel,f IN=1kHz,22kHz BW,Both channels in phase0.65%X TALK Channel Separation P O=100mW RMS,f=1kHz57dBR IN Differential Input Resistance V Gain Select=V DD90kΩV Gain Select=GND60kΩPSRR Power Supply Rejection Ratio V Ripple=100mV RMS sine wave,f RIPPLE=217HzInputs terminated to AC GND60dBV Ripple=100mV RMS sine wave,f RIPPLE=217HzP OUT=10mW,1kHz65dBCMRR Common Mode Rejection Ratio V Ripple=100mV RMS,f Ripple=217Hz,Input referred48dBSNR Signal to Noise Ratio P O=1W RMS;A-Weighted Filter83dBe OUT Output Noise A-Weighted filter,V in=0V200µVLM46663Electrical Characteristics V DD =3V(Notes 1,2)The following specifications apply for V DD =3V and R L =15µH +8Ω+15µH unless otherwise specified.Limits apply for T A =25˚C.Symbol ParameterConditionsLM4666Units (Limits)Typical Limit (Note 6)(Notes 7,8)I DD Quiescent Power Supply Current V IN =0V,No LoadV IN =0V,R L =15µH +8Ω+15µH 6.57.010mA (max)I SD Shutdown CurrentV SD =GND (Note 9)0.02 2.0µA (max)V SDIH Shutdown Voltage Input High 1.0 1.4V (min)V SDIL Shutdown Voltage Input Low 0.80.4V (max)V GSIH Gain Select Input High 1.0 1.4V (min)V GSIL Gain Select Input Low 0.80.4V (max)A V Closed Loop Gain V Gain Select=V DD 6 5.256.75dB (min)dB (max)A V Closed Loop Gain V GainSelect=GND1211.2512.75dB (min)dB (max)V OS Output Offset Voltage 1035mV (max)T WU Wake-up Time 6msP oOutput PowerTHD =1%(max);f =1kHz,22kHz BW450400mW (min)THD+N Total Harmonic Distortion+Noise P O =100mW RMS /Channel,f IN =1kHz,22kHz BW,Both channels in phase 0.65%X TALK Channel Separation P O =100mW RMS ,f =1kHz 57dB R INDifferential Input ResistanceV Gain Select =V DD 90k ΩV GainSelect=GND60k ΩPSRR Power Supply Rejection RatioV ripple =100mV RMS sine wave,f RIPPLE =217Hz,Inputs terminated to AC GND 60dBV Ripple =100mV RMS sine wave,f RIPPLE =217Hz,P OUT =10mW,1kHz65dBCMRR Common Mode Rejection Ratio V Ripple =100mV RMS ,f Ripple =217Hz,Input referred 48dB SNR Signal to Noise Ratio P O =400mW RMS ,A-Weighted Filter 83dB e OUTOutput NoiseA-Weighted filter,V in =0V125µVNote 1:All voltages are measured with respect to the ground pin,unless otherwise specified.Note 2:Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.Operating Ratings indicate conditions for which the device is functional,but do not guarantee specific performance limits.Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits.This assumes that the device is within the Operating Ratings.Specifications are not guaranteed for parameters where no limit is given,however,the typical value is a good indication of device performance.Note 3:The maximum power dissipation must be derated at elevated temperatures and is dictated by T JMAX ,θJA ,and the ambient temperature T A .The maximum allowable power dissipation is P DMAX =(T JMAX –T A )/θJA or the number given in Absolute Maximum Ratings,whichever is lower.For the LM4666,T JMAX =150˚C.The typical θJA is 63˚C/W and the typical θJC is 12˚C/W for the SDA package.Note 4:Human body model,100pF discharged through a 1.5k Ωresistor.Note 5:Machine Model,220pF –240pF discharged through all pins.Note 6:Typical specifications are specified at 25˚C and represent the parametric norm.Note 7:Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).Note 8:Datasheet min/max specification limits are guaranteed by design,test,or statistical analysis.Note 9:Shutdown current is measured in a normal room environment.Exposure to direct sunlight will increase I SD by a maximum of 2µA.The Shutdown pin should be driven as close as possible to GND for minimal shutdown current and to V DD for the best THD performance in PLAY mode.See the Application Information section under SHUTDOWN FUNCTION for more information.Note 10:The performance graphs were taken using the Audio Precision AUX–0025Switching Amplifier Measurement Filter in series with the LC filter on the demo board.L M 4666 4External Components Description(Figure 1)Components Functional Description1.C S Supply bypass capacitor which provides power supply filtering.Refer to the Power Supply Bypassing section for information concerning proper placement and selection of the supply bypass capacitor.2.C IInput AC coupling capacitor which blocks the DC voltage at the amplifier’s input terminals.Typical Performance Characteristics(Note 10)THD+N vs FrequencyV DD =5V,R L =15µH +8Ω+15µH P OUT =100mW/Channel,30kHz BWTHD+N vs FrequencyV DD =3V,R L =15µH +8Ω+15µH P OUT =100mW/Channel,30kHz BW2005582720055826THD+N vs FrequencyV DD =3V,R L =15µH +4Ω+15µH P OUT =100mW/Channel,30kHz BWTHD+N vs Output Power/Channel V DD =5V,R L =15µH +8Ω+15µHf =1kHz,22kHz BW2005582520055830LM46665Typical Performance Characteristics(Note 10)(Continued)THD+N vs Output Power/Channel V DD =3V,R L =15µH +4Ω+15µHf =1kHz,22kHz BWTHD+N vs Output Power/Channel V DD =3V,R L =15µH +8Ω+15µHf =1kHz,22kHz BW2005582820055829CMRR vs FrequencyV DD =5V,R L =15µH +8Ω+15µH V CM =100mV RMS Sine Wave,30kHz BW CMRR vs FrequencyV DD =3V,R L =15µH +8Ω+15µH V CM =100mV RMS Sine Wave,30kHz BW2005581120055810PSRR vs FrequencyV DD =5V,R L =15µH +8Ω+15µHV Ripple =100mV RMS Sine Wave,22kHz BW PSRR vs FrequencyV DD =3V,R L =15µH +8Ω+15µHV Ripple =100mV RMS Sine Wave,22kHz BW2005581920055818L M 4666 6Typical Performance Characteristics(Note10)(Continued)Efficiency and Power Dissipationvs Output PowerV DD=5V,R L=15µH+8Ω+15µH,f=1kHz,THD≤1%Efficiency and Power Dissipationvs Output PowerV DD=3V,R L=15µH+8Ω+15µH,f=1kHz,THD≤1%2005581420055813Efficiency and Power Dissipationvs Output PowerV DD=3V,R L=15µH+4Ω+15µH,f=1kHz,THD≤1%Gain Select ThresholdV DD=3V20055812200558H6Gain Select ThresholdV DD=5VGain Select Thresholdvs Supply VoltageR L=15µH+8Ω+15µH200558H120055815LM4666 7Typical Performance Characteristics(Note 10)(Continued)Output Power/Channel vs Supply VoltageR L =15µH +8Ω+15µH,f =1kHz22kHz BWOutput Power/Channel vs Supply VoltageR L =15µH +4Ω+15µH,f =1kHz22kHz BW2005581720055816Shutdown ThresholdV DD =5V Shutdown ThresholdV DD =3V2005582220055821Shutdown Threshold vs Supply Voltage R L =15µH +8Ω+15µH Supply Current vs Shutdown Voltage R L =15µH +8Ω+15µH2005582020055823L M 4666 8LM4666 Typical Performance Characteristics(Note10)(Continued)Supply Currentvs Supply VoltageR L=15µH+8Ω+15µH Array 200558249Application InformationGENERAL AMPLIFIER FUNCTIONThe output signals generated by the LM4666consist of two,BTL connected,output signals that pulse momentarily from near ground potential to V DD on each channel.The two outputs on a given channel can pulse independently with the exception that they both may never pulse simultaneously as this would result in zero volts across the BTL connected load.The minimum width of each pulse is approximately 160ns.However,pulses on the same output can occur se-quentially,in which case they are concatenated and appear as a single wider pulse to achieve an effective 100%duty cycle.This results in maximum audio output power for a given supply voltage and load impedance.The LM4666can achieve much higher efficiencies than class AB amplifiers while maintaining acceptable THD performance.The short (160ns)drive pulses emitted at the LM4666out-puts means that good efficiency can be obtained with mini-mal load inductance.The typical transducer load on an audio amplifier is quite reactive (inductive).For this reason,the load can act as it’s own filter,so to speak.This "filter-less"switching amplifier/transducer load combination is much more attractive economically due to savings in board space and external component cost by eliminating the need for a filter.POWER DISSIPATION AND EFFICIENCYIn general terms,efficiency is considered to be the ratio of useful work output divided by the total energy required to produce it with the difference being the power dissipated,typically,in the IC.The key here is “useful”work.For audio systems,the energy delivered in the audible bands is con-sidered useful including the distortion products of the input signal.Sub-sonic (DC)and super-sonic components (>22kHz)are not useful.The difference between the power flowing from the power supply and the audio band power being transduced is dissipated in the LM4666and in the transducer load.The amount of power dissipation in the LM4666is very low.This is because the ON resistance of the switches used to form the output waveforms is typically less than 0.25Ω.This leaves only the transducer load as a po-tential "sink"for the small excess of input power over audio band output power.The LM4666dissipates only a fraction of the excess power requiring no additional PCB area or cop-per plane to act as a heat sink.DIFFERENTIAL AMPLIFIER EXPLANATIONAs logic supply voltages continue to shrink,designers are increasingly turning to differential analog signal handling to preserve signal to noise ratios with restricted voltage swing.The LM4666is a fully differential amplifier that features differential input and output stages.A differential amplifier amplifies the difference between the two input signals.Tra-ditional audio power amplifiers have typically offered only single-ended inputs resulting in a 6dB reduction in signal to noise ratio relative to differential inputs.The LM4666also offers the possibility of DC input coupling which eliminates the two external AC coupling,DC blocking capacitors.The LM4666can be used,however,as a single ended input amplifier while still retaining it’s fully differential benefits.In fact,completely unrelated signals may be placed on the input pins.The LM4666simply amplifies the difference be-tween the signals.A major benefit of a differential amplifier isthe improved common mode rejection ratio (CMRR)over single input amplifiers.The common-mode rejection charac-teristic of the differential amplifier reduces sensitivity to ground offset related noise injection,especially important in high noise applications.PCB LAYOUT CONSIDERATIONSAs output power increases,interconnect resistance (PCB traces and wires)between the amplifier,load and power supply create a voltage drop.The voltage loss on the traces between the LM4666and the load results is lower output power and decreased efficiency.Higher trace resistance between the supply and the LM4666has the same effect as a poorly regulated supply,increase ripple on the supply line also reducing the peak output power.The effects of residual trace resistance increases as output current increases due to higher output power,decreased load impedance or both.To maintain the highest output voltage swing and corre-sponding peak output power,the PCB traces that connect the output pins to the load and the supply pins to the power supply should be as wide as possible to minimize trace resistance.The rising and falling edges are necessarily short in relation to the minimum pulse width (160ns),having approximately 2ns rise and fall times,typical,depending on parasitic output capacitance.The inductive nature of the transducer load can also result in overshoot on one or both edges,clamped by the parasitic diodes to GND and V DD in each case.From an EMI standpoint,this is an aggressive waveform that can radiate or conduct to other components in the system and cause interference.It is essential to keep the power and output traces short and well shielded if e of ground planes,beads,and micro-strip layout techniques are all useful in preventing unwanted interference.As the distance from the LM4666and the speakers increase the amount of EMI radiation will increase since the output wires or traces acting as antenna become more efficient with length.What is acceptable EMI is highly application specific.Ferrite chip inductors placed close to the LM4666may be needed to reduce EMI radiation.The value of the ferrite chip is very application specific.POWER SUPPLY BYPASSINGAs with any power amplifier,proper supply bypassing is critical for low noise performance and high power supply rejection ratio (PSRR).The capacitor (C S )location should be as close as possible to the LM4666.Typical applications employ a voltage regulator with a 10µF and a 0.1µF bypass capacitors that increase supply stability.These capacitors do not eliminate the need for bypassing on the supply pin of the LM4666.A 1µF tantalum capacitor is recommended.SHUTDOWN FUNCTIONIn order to reduce power consumption while not in use,the LM4666contains shutdown circuitry that reduces current draw to less than 0.01µA.The trigger point for shutdown is shown as a typical value in the Electrical Characteristics Tables and in the Shutdown Hysteresis Voltage graphs found in the Typical Performance Characteristics section.It is best to switch between ground and supply for minimum current usage while in the shutdown state.While the LM4666may be disabled with shutdown voltages in between ground and supply,the idle current will be greater than theL M 466610Application Information(Continued) typical value.Increased THD may also be observed with voltages less than V DD on the Shutdown pin when in PLAY mode.The LM4666has an internal resistor connected between GND and Shutdown pins.The purpose of this resistor is to eliminate any unwanted state changes when the Shutdown pin is floating.The LM4666will enter the shutdown state when the Shutdown pin is left floating or if not floating,when the shutdown voltage has crossed the threshold.To mini-mize the supply current while in the shutdown state,the Shutdown pin should be driven to GND or left floating.If the Shutdown pin is not driven to GND,the amount of additional resistor current due to the internal shutdown resistor can be found by Equation(1)below.(V SD-GND)/60kΩ(1)With only a0.5V difference,an additional8.3µA of currentwill be drawn while in the shutdown state.GAIN SELECTION FUNCTIONThe LM4666has fixed selectable gain to minimize externalcomponents,increase flexibility and simplify design.For adifferential gain of6dB,the Gain Select pin should be per-manently connected to V DD or driven to a logic high level.For a differential gain of12dB,the Gain Select pin should bepermanently connected to GND or driven to a logic low level.The gain of the LM4666can be switched while the amplifieris in PLAY mode driving a load with a signal without damageto the IC.The voltage on the Gain Select pin should beswitched quickly between GND(logic low)and V DD(logichigh)to eliminate any possible audible artifacts from appear-ing at the output.For typical threshold voltages for the GainSelect function,refer to the Gain Threshold Voltages graphin the Typical Performance Characteristics section.LM466611Application Information(Continued)CIRCUIT CONFIGURATIONS20055803FIGURE 2.Single-Ended input with low gain selection configuration20055802FIGURE 3.Differential input with low gain selection configurationL M 4666 12Application Information(Continued) REFERENCE DESIGN BOARD SCHEMATICIn addition to the minimal parts required for the application circuit,a measurement filter is provided on the evaluation circuit board so that conventional audio measurements can be conveniently made without additional equipment.This is a balanced input,grounded differential output low pass filter with a3dB frequency of approximately35kHz and an on board termination resistor of300Ω(see schematic).Note that the capacitive load elements are returned to ground. This is not optimal for common mode rejection purposes,but due to the independent pulse format at each output there is a significant amount of high frequency common mode com-ponent on the outputs.The grounded capacitive filter ele-ments attenuate this component at the board to reduce the high frequency CMRR requirement placed on the analysis instruments.Even with the grounded filter the audio signal is still differ-ential necessitating a differential input on any analysis instru-ment connected to it.Most lab instruments that feature BNC connectors on their inputs are NOT differential responding because the ring of the BNC is usually grounded.The commonly used Audio Precision analyzer is differential but its ability to accurately reject fast pulses of160ns width is questionable necessitating the on board measurement filter. When the signal needs to be single-ended,use an audio signal transformer to convert the differential output to a single ended output.Depending on the audio transformer’s characteristics,there may be some attenuation of the audio signal which needs to be taken into account for correct measurement of performance.Measurements made at the output of the measurement filter suffer attenuation relative to the primary,unfiltered outputs even at audio frequencies.This is due to the resistance of the inductors interacting with the termination resistor(300Ω) and is typically about-0.35dB(4%).In other words,the voltage levels and corresponding power levels indicated through the measurement filter are slightly lower than those that actually occur at the load placed on the unfiltered out-puts.This small loss in the filter for measurement gives a lower output power reading than what is really occurring on the unfiltered outputs and its load.The AUX-0025Switching Amplifier Measurement Filter from Audio Precision may be used instead of the on board mea-surement filter.The AUX-0025filter should be connected to the high current direct outputs on the evaluation board and in series with the measurement equipment.Attaching oscillo-scope probes on the outputs of the AUX-0025filter will display the audio waveforms.The AUX-0025filter may also be connected to the on board filter without any adverse effects.20055801FIGURE4.LM4666 13Application Information(Continued)LM4666SDA BOARD ARTWORKComposite ViewSilk Screen2005580520055808Top Layer Internal Layer 1,GND2005580920055806Internal Layer 2,V DDBottom Layer2005580720055804L M 4666 14Physical Dimensionsinches (millimeters)unless otherwise notedLLP PackageOrder NumberLM4666SD NS Package Number SDA14ALIFE SUPPORT POLICYNATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION.As used herein:1.Life support devices or systems are devices or systems which,(a)are intended for surgical implant into the body,or (b)support or sustain life,and whose failure to perform when properly used in accordance with instructions for use provided in the labeling,can be reasonably expected to result in a significant injury to the user. 2.A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system,or to affect its safety or effectiveness.BANNED SUBSTANCE COMPLIANCENational Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products Stewardship Specification (CSP-9-111C2)and the Banned Substances and Materials of Interest Specification (CSP-9-111S2)and contain no ‘‘Banned Substances’’as defined in CSP-9-111S2.National Semiconductor Americas Customer Support CenterEmail:new.feedback@ Tel:1-800-272-9959National SemiconductorEurope Customer Support CenterFax:+49(0)180-5308586Email:europe.support@Deutsch Tel:+49(0)6995086208English Tel:+44(0)8702402171Français Tel:+33(0)141918790National Semiconductor Asia Pacific Customer Support CenterEmail:ap.support@National SemiconductorJapan Customer Support Center Fax:81-3-5639-7507Email:jpn.feedback@ Tel:81-3-5639-7560LM4666Filterless High Efficiency Stereo 1.2W Switching Audio AmplifierNational does not assume any responsibility for use of any circuitry described,no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.。