Transceivers Using Four 0.1µF External Capacitors
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232________________General Description
__Next Generation Device Features
The MAX3222/MAX3232/MAX3237/MAX3241 trans-ceivers have a proprietary low-dropout transmitter out-♦For Smaller Packaging:
MAX3228E/MAX3229E: +2.5V to +5.5V RS-232put stage enabling true RS-232 performance from aTransceivers in UCSP™
3.0V to 5.5V supply with a dual charge pump. Thedevices require only four small 0.1µF external charge-♦For Integrated ESD Protection:
pump capacitors. The MAX3222, MAX3232, andMAX3222E/MAX3232E/MAX3237E/MAX3241E*/MAX3241 are guaranteed to run at data rates ofMAX3246E: ±15kV ESD-Protected, Down to 10nA,120kbps while maintaining RS-232 output levels. The3.0V to 5.5V, Up to 1Mbps, True RS-232MAX3237 is guaranteed to run at data rates of 250kbpsTransceivers
in the normal operating mode and 1Mbps in the♦For Low-Voltage or Data Cable Applications:MegaBaud™ operating mode, while maintaining RS-232MAX3380E/MAX3381E: +2.35V to +5.5V, 1µA, output levels.
2 Tx/2 Rx RS-232 Transceivers with ±15kV ESD-Protected I/O and Logic Pins
The MAX3222/MAX3232 have 2 receivers and 2 drivers. The MAX3222 features a 1µA shutdown modethat reduces power consumption and extends batterylife in portable systems. Its receivers remain active inshutdown mode, allowing external devices such as_______________Ordering Informationmodems to be monitored using only 1µA supply cur-rent. The MAX3222 and MAX3232 are pin, package,PARTTEMP RANGEPIN-PACKAGEPKGand functionally compatible with the industry-standardCODEMAX242 and MAX232, respectively.
MAX3222CUP+0°C to +70°C20 TSSOPU20+2The MAX3241 is a complete serial port (3 drivers/MAX3222CAP+0°C to +70°C20 SSOPA20+15 receivers) designed for notebook and subnotebookMAX3222CWN+0°C to +70°C18 SOW18+1computers. The MAX3237 (5 drivers/3 receivers) is idealMAX3222CPN+0°C to +70°C18 Plastic DipP18+5for fast modem applications. Both these devices featurea shutdown mode in which all receivers can remain+Denotes lead-free package.
active while using only 1µA supply current. Receivers R1(MAX3237/MAX3241) and R2 (MAX3241) have extra out-puts in addition to their standard outputs. These extraoutputs are always active, allowing external devicesOrdering Information continued at end of data sheet.
such as a modem to be monitored without forward bias-ing the protection diodes in circuitry that may have VCCcompletely removed.
_________________Pin ConfigurationsThe MAX3222, MAX3237, and MAX3241 are availablein space-saving TSSOP and SSOP packages.
TOP VIEW+EN118SHDN________________________Applications
C1+217VCCNotebook, Subnotebook, and Palmtop ComputersV+316GNDHigh-Speed ModemsC1-4MAX322215T1OUTBattery-Powered EquipmentC2+5MAX322214R1INHand-Held EquipmentC2-613R1OUTV-712T1INPeripheralsT2OUT811T2INPrinters
R2IN910R2OUTTypical Operating Circuits appear at end of data sheet.
DIP/SOPin Configurations continued at end of data sheet.MegaBaud and UCSP are trademarks 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.
________________________________________________________________Maxim Integrated Products
1
For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAX3222/MAX3232/MAX3237/MAX3241*元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241ABSOLUTE MAXIMUM RATINGS
VCC...........................................................................-0.3V to +6VV+ (Note 1)...............................................................-0.3V to +7VV- (Note 1)................................................................+0.3V to -7VV+ + V- (Note 1)...................................................................+13VInput Voltages
T_IN, SHDN, EN...................................................-0.3V to +6VMBAUD...................................................-0.3V to (VCC+ 0.3V)R_IN.................................................................................±25VOutput Voltages
T_OUT...........................................................................±13.2VR_OUT....................................................-0.3V to (VCC+ 0.3V)Short-Circuit Duration
T_OUT....................................................................Continuous
Continuous Power Dissipation (TA= +70°C)
16-Pin TSSOP (derate 6.7mW/°C above +70°C).............533mW16-Pin Narrow SO (derate 8.70mW/°C above +70°C)....696mW16-Pin Wide SO (derate 9.52mW/°C above +70°C)........762mW16-Pin Plastic DIP (derate 10.53mW/°C above +70°C)...842mW18-Pin SO (derate 9.52mW/°C above +70°C)..............762mW18-Pin Plastic DIP (derate 11.11mW/°C above +70°C)..889mW20-Pin SSOP (derate 7.00mW/°C above +70°C).........559mW20-Pin TSSOP (derate 8.0mW/°C above +70°C).............640mW28-Pin TSSOP (derate 8.7mW/°C above +70°C).............696mW28-Pin SSOP (derate 9.52mW/°C above +70°C).........762mW28-Pin SO (derate 12.50mW/°C above +70°C).....................1WOperating Temperature Ranges
MAX32_ _C_ _.....................................................0°C to +70°CMAX32_ _E_ _ .................................................-40°C to +85°CStorage Temperature Range.............................-65°C to +150°CLead Temperature (soldering, 10s).................................+300°C
Note 1:V+ and V- can have a maximum magnitude of 7V, but their absolute difference cannot exceed 13V.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERDC CHARACTERISTICS VCCPower-Supply CurrentShutdown Supply CurrentInput Logic Threshold Low(Note 3)Input Logic Threshold High(Note 3)Input Leakage CurrentOutput Leakage CurrentOutput Voltage LowOutput Voltage HighRECEIVER INPUTS Input Voltage RangeInput Threshold LowInput Threshold HighTA= +25°CTA= +25°CVCC= 5.0VVCC= 3.3VVCC= 5.0VVCC= 3.3VVCC= 5.0V-250.60.81.21.51.51.82.42.425VVVNo load, VCC= 3.3V or 5.0V,TA= +25°CSHDN = GND, TA= +25°CMAX3222/MAX3232/MAX3241MAX32370.30.51.01.02.010µAmACONDITIONSMINTYPMAXUNITSLOGIC INPUTS AND RECEIVER OUTPUTS T_IN, EN, SHDN, MBAUDVCC= 3.3VVCC= 5.0VT_IN, EN, SHDN, MBAUDReceivers disabledIOUT= 1.6mAIOUT= -1.0mAVCC- 0.6VCC- 0.12.02.4±0.01±0.05±1.0±100.40.8VVµAµAVV2_______________________________________________________________________________________
元器件交易网www.cecb2b.comTransceivers Using Four 0.1µF External Capacitors
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERCONDITIONSMINTYPMAXUNITSInput Hysteresis0.3VInput ResistanceTA= +25°C357kΩTRANSMITTER OUTPUTS Output Voltage SwingAll transmitter outputs loaded with 3kΩto ground±5.0±5.4VOutput ResistanceVCC= V+ = V- = 0V, TOUT= ±2V30010MΩOutput Short-Circuit Current±35±60mAOutput Leakage CurrentVOUT= ±12V, VCC= 0V or 3V to 5.5V, transmitters disabled±25µAMOUSE DRIVEABILITY (MAX3241)T1IN = T2IN = GND, T3IN = VCC,Transmitter Output VoltageT3OUT loaded with 3kΩto GND,±5.0VT1OUT and T2OUT loaded with 2.5mA eachTIMING CHARACTERISTICS—MAX3222/MAX3232/MAX3241
(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERCONDITIONSMINTYPMAXUNITSMaximum Data RateRL= 3kΩ, CL= 1000pF, one transmitter switching120235kbpsReceiver Propagation DelayR_IN to R_OUT, CL= 150pFtPHL0.3tµsPLH0.3Receiver Output Enable TimeNormal operation200nsReceiver Output Disable TimeNormal operation200nsTransmitter Skew|tPHL- tPLH|300nsReceiver Skew|tPHL- tPLH|300nsVCC= 3.3V, RL= 3kΩto 7kΩ, CL= 150pF to1000pF630Transition-Region Slew Rate+3V to -3V or -3V to +3V,TA= +25°C, one transmitterCV/µsswitchingL= 150pF to2500pF430_______________________________________________________________________________________3
MAX3222/MAX3232/MAX3237/MAX3241元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241TIMING CHARACTERISTICS—MAX3237
(VCC= +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERCONDITIONSRL= 3kΩ, CL= 1000pF, one transmitter switching,MBAUD = GNDMaximum Data RateVCC= 3.0V to 4.5V, RL= 3kΩ, CL= 250pF,one transmitter switching, MBAUD = VCCVCC= 4.5V to 5.5V, RL= 3kΩ, CL= 1000pF,one transmitter switching, MBAUD = VCCReceiver Propagation DelayReceiver Output Enable TimeR_IN to R_OUT, CL= 150pFNormal operationtPHLtPLHMIN250100010000.150.152002001002550CL= 150pFto 1000pFMBAUD =GNDMBAUD =VCC62443015030V/µsµsnsnsnsnsnskbpsTYPMAXUNITSReceiver Output Disable TimeNormal operationTransmitter SkewReceiver Skew|tPHL- tPLH|, MBAUD = GND|tPHL- tPLH|, MBAUD = VCC|tPHL- tPLH|Transition-Region Slew RateVCC= 3.3V, RL= 3Ωto 7kΩ,+3V to -3V or -3V to +3V,TA= +25°CCL= 150pF to 2500pF,MBAUD = GNDNote 2:MAX3222/MAX3232/MAX3241: C1–C4 = 0.1µF tested at 3.3V ±10%; C1 = 0.047µF, C2–C4 = 0.33µF tested at 5.0V ±10%.
MAX3237: C1–C4 = 0.1µF tested at 3.3V ±5%; C1–C4 = 0.22µF tested at 3.3V ±10%; C1 = 0.047µF, C2–C4 = 0.33µF testedat 5.0V ±10%.
Note 3:Transmitter input hysteresis is typically 250mV.
__________________________________________Typical Operating Characteristics
(VCC= +3.3V, 235kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
MAX3222/MAX3232
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3222-01MAX3222/MAX3232
SLEW RATE
vs. LOAD CAPACITANCE
2018SLEW RATE (V/µs)1614121086420
5000
150
1000
2000
3000
4000
5000
+SLEW-SLEWFOR DATA RATES UP TO 235kbpsMAX3222-02MAX3222/MAX3232
SUPPLY CURRENT vs. LOAD CAPACITANCE
WHEN TRANSMITTING DATA
35SUPPLY CURRENT (mA)3025
120kbps2015
20kbps1050
0
1000
2000
3000
4000
5000
MAX3222-03TRANSMITTER OUTPUT VOLTAGE (V)6543210-1-2-3-4-5-6
0
1000
2000
3000
2240
235kbpsVOUT+VOUT-4000
LOAD CAPACITANCE (pF)LOAD CAPACITANCE (pF)LOAD CAPACITANCE (pF)
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元器件交易网www.cecb2b.comTransceivers Using Four 0.1µF External Capacitors
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232_____________________________Typical Operating Characteristics (continued)
(VCC= +3.3V, 235kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)
MAX3241
MAX3241MAX3241
TRANSMITTER OUTPUT VOLTAGE
SLEW RATE
SUPPLY CURRENT vs. LOAD
vs. LOAD CAPACITANCE
vs. LOAD CAPACITANCE
CAPACITANCE WHEN TRANSMITTING DATA
7.54024545
6-002-)2222VVOUT+3222235kbps-222X33AXX(MAA EM40MG5.0A20)TA35LO)smµ18(V2.5 1 TRANSMITTER AT 235kbps/T30TV-SLEWN120kbpsU2 TRANSMITTERS AT 30kbps( EPE16TTRU0AR25OR14U CRW Y20ETE12L-2.5LP20kbpsTIS10+SLEWP15MUSSN8ALL OUTPUTS LOADED WITH 3kΩ +C10AR-5.0VOUT-L T60.1µF CHARGE-PUMP CAPACITORS5-7.5
4
FOR ALL DATA RATES UP TO 235kbps0
0
1000
2000
3000
40005000
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
MAX3237
MAX3237
MAX3237
TRANSMITTER OUTPUT VOLTAGETRANSMITTER OUTPUT VOLTAGESLEW RATE vs. LOAD CAPACITANCE
vs. LOAD CAPACITANCE (MBAUD = GND)
vs. LOAD CAPACITANCE (MBAUD = VCC)
(MBAUD = GND)
7.5707.58129-00-2-)2222V3)2222X(AV1Mbps33XX M(AAE MMG5.0EG5.010-SLEWATA2MbpsLTL1.5Mbps)OOs+SLEWV2.5V2.5µ 1 TRANSMITTER AT 240kbps/8T TVUU(4 TRANSMITTERS AT 15kbps1 TRANSMITTER AT FULL DATA RATE PPETTTU03kΩ + C4 TRANSMITTERS AT 1/16 DATA RATEL LOADSU0AOOR6V3kΩ + CL LOAD, EACH OUTPUT RCC = 3.3V REVCC = 3.3VWETET-2.5TLIT-2.5S4
MISMS1 TRANSMITTER AT 240kbpsNANR-5.0A4 TRANSMITTERS AT 15kbpsTR-5.02Mbps1.5Mbps2T1Mbps3kΩ + CL LOADSVCC = 3.3V-7.5
-7.5
00
1000
2000
3000
4000
50000
500
1000
1500
2000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
MAX3237
MAX3237
MAX3237
SLEW RATE vs. LOAD CAPACITANCE
SUPPLY CURRENT vs.
SKEW vs. LOAD CAPACITANCE
(MBAUD = VCC)
LOAD CAPACITANCE (MBAUD = GND)
(tPLH - tPHL)
70060111--2270
21222233XX1 TRANSMITTER AT 512kbps-)2s2260AAnMM604 TRANSMITTERS AT 32kbps3X(A M-SLEW, 1Mbps50W)240kbpsE3kΩ + CL LOADS+SLEW, 1MbpsAmK)s50(-SLEW, 2Mbps50SVµ T40120kbpsMBAUD = VCC = 3.3VCC/V( E+SLEW, 2MbpsNERT40R40
MAXARU30
C AVERAGE; 10 PARTSW30Y20kbpsEL30LPSP20U201 TRANSMITTER AT FULL DATA RATES1 TRANSMITTER AT FULL DATA RATE20104 TRANSMITTERS AT 1/16 DATA RATE3kΩ + C104 TRANSMITTERS AT 1/16 DATA RATE3kΩ + C10V = 3.3VL LOADSMINCC0VL LOAD EACH OUTPUTCC = 3.3V0
0
500
1000
1500
20000
1000
2000
3000
4000
5000
0
0
500
1000
1500
2000
2500
LOAD CAPACITANCE (pF)LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
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MAX3222/MAX3232/MAX3237/MAX3241元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241______________________________________________________________Pin Description
PINMAX3222DIP/SO12345678, 159, 1410, 1311, 12161718———SSOP12345678, 179, 1610, 1512, 1318192011, 14——MAX3232—1234567, 148, 139, 1210, 111516————MAX3237132827251345, 6, 7, 10, 128, 9, 1118, 20, 2117, 19, 22,23, 2422614—1516MAX3241232827241239, 10, 114–815–1912, 13, 14252622——20, 21NAMEFUNCTIONENC1+V+C1-C2+C2-V-T_OUTR_INR_OUTT_INGNDVCCSHDNN.C.MBAUDR_OUTBReceiver Enable. Active low.Positive Terminal of Voltage-Doubler Charge-PumpCapacitor+5.5V Generated by the Charge PumpNegative Terminal of Voltage-Doubler Charge-PumpCapacitorPositive Terminal of Inverting Charge-PumpCapacitorNegative Terminal of Inverting Charge-PumpCapacitor-5.5V Generated by the Charge PumpRS-232 Transmitter OutputsRS-232 Receiver InputsTTL/CMOS Receiver OutputsTTL/CMOS Transmitter InputsGround+3.0V to +5.5V Supply VoltageShutdown Control. Active low.No ConnectionMegaBaud Control Input. Connect to GND for normaloperation; connect to VCCfor 1Mbps transmission rates.Noninverting Complementary Receiver Outputs.Always active.6_______________________________________________________________________________________
元器件交易网www.cecb2b.comTransceivers Using Four 0.1µF External Capacitors
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232_______________Detailed Description
The MAX3222/MAX3237/MAX3241’s output stage isDual Charge-Pump Voltage Converter
turned off (high impedance) when the device is in shut-The MAX3222/MAX3232/MAX3237/MAX3241’s internaldown mode. When the power is off, the MAX3222/power supply consists of a regulated dual charge pumpMAX3232/MAX3237/MAX3241 permit the outputs to bethat provides output voltages of +5.5V (doubling chargedriven up to ±12V.
pump) and -5.5V (inverting charge pump), regardless ofThe transmitter inputs do not have pullup resistors.the input voltage (VCC) over the 3.0V to 5.5V range. TheConnect unused inputs to GND or VCC.
charge pumps operate in a discontinuous mode; if theoutput voltages are less than 5.5V, the charge pumpsMAX3237 MegaBaud Operation
are enabled, and if the output voltages exceed 5.5V, theIn normal operating mode (MBAUD = GND), thecharge pumps are disabled. Each charge pumpMAX3237 transmitters guarantee a 250kbps data raterequires a flying capacitor (C1, C2) and a reservoirwith worst-case loads of 3kΩin parallel with 1000pF.capacitor (C3, C4) to generate the V+ and V- supplies.
This provides compatibility with PC-to-PC communica-tion software, such as Laplink.
RS-232 Transmitters
For higher speed serial communications, the MAX3237The transmitters are inverting level translators that con-features MegaBaud operation. In MegaBaud operatingvert CMOS-logic levels to 5.0V EIA/TIA-232 levels.
mode (MBAUD = VCC), the MAX3237 transmitters guar-The MAX3222/MAX3232/MAX3241 transmitters guaran-antee a 1Mbps data rate with worst-case loads of 3kΩintee a 120kbps data rate with worst-case loads of 3kΩinparallel with 250pF for 3.0V < VCC < 4.5V. For 5V ±10%parallel with 1000pF, providing compatibility with PC-to-operation, the MAX3237 transmitters guarantee a 1MbpsPC communication software (such as LapLink™).data rate into worst-case loads of 3kΩin parallel withTypically, these three devices can operate at data rates1000pF.
of 235kbps. Transmitters can be paralleled to drive multi-ple receivers or mice.
LapLink is a trademark of Traveling Software, Inc.
VCCVCC 0.1µF 0.1µFC1+VCCV+C1+VCCV+C1 C1-C3C1 C1-C3C2+MAX3222MAX3222MAX3232V-C2+MAX3232V-C2 C2-MAX3237C4C2 C2-MAX3237C4MAX3241MAX3241T_ INT_ OUTT_ INT_ OUTR_ OUTR_ INR_ OUTR_ IN0VEN*5kΩ0VEN*5kΩVCCSHDN*3kΩ2500pFVGNDCCSHDN*GND7kΩ150pF* MAX3222/MAX3241 ONLYMINIMUM SLEW-RATE TEST CIRCUITMAXIMUM SLEW-RATE TEST CIRCUITFigure 1. Slew-Rate Test Circuits
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MAX3222/MAX3232/MAX3237/MAX3241元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241RS-232 Receivers
VCCVCCRxPROTECTIONDIODEUARTTxGNDSHDN = GNDPREVIOUSRS-2325kΩThe receivers convert RS-232 signals to CMOS-logic out-put levels. The MAX3222/MAX3237/MAX3241 receivershave inverting three-state outputs. In shutdown, thereceivers can be active or inactive (Table 1).
The complementary outputs on the MAX3237 (R1OUTB)and the MAX3241 (R1OUTB, R2OUTB) are always active,regardless of the state of ENor SHDN. This allows forRing Indicator applications without forward biasing otherdevices connected to the receiver outputs. This is idealfor systems where VCCis set to 0V in shutdown toaccommodate peripherals, such as UARTs (Figure 2).
MAX3222/MAX3237/MAX3241
Shutdown Mode
Supply current falls to less than 1µA in shutdown mode(SHDN= low). When shut down, the device’s chargepumps are turned off, V+ is pulled down to VCC, V- ispulled to ground, and the transmitter outputs are dis-abled (high impedance). The time required to exit shut-down is typically 100µs, as shown in Figure 3. ConnectSHDN to VCCif the shutdown mode is not used. SHDNhas no effect on R_OUT or R_OUTB.
a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE RECEIVER OUTPUT IN SHUTDOWN.VCCTOµPLOGICTRANSITIONDETECTORMAX3222/MAX3237/MAX3241
Enable Control
The inverting receiver outputs (R_OUT) are put into ahigh-impedance state when ENis high. The complemen-tary outputs R1OUTB and R2OUTB are always active,regardless of the state of ENand SHDN(Table 1). ENhas no effect on T_OUT.
MAX3237MAX3241R1OUTBVCCRxPROTECTIONDIODEUARTTxGNDT1INSHDN = GNDR1OUTEN = VCC5kΩT1OUTR1IN__________Applications Information
Capacitor Selection
The capacitor type used for C1–C4 is not critical forproper operation; polarized or nonpolarized capacitorscan be used. The charge pump requires 0.1µF capaci-tors for 3.3V operation. For other supply voltages, refer toTable 2 for required capacitor values. Do not use valueslower than those listed in Table 2. Increasing the capaci-tor values (e.g., by a factor of 2) reduces ripple on thetransmitter outputs and slightly reduces power consump-tion. C2, C3, and C4 can be increased without changingC1’s value. However, do not increase C1 without alsoincreasing the values of C2, C3, and C4, to maintain theproper 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 ahigher nominal value. The capacitor’s equivalent seriesresistance (ESR), which usually rises at low tempera-tures, influences the amount of ripple on V+ and V-.
b) NEW MAX3237/MAX3241: EN SHUTS DOWN RECEIVER OUTPUTS (EXCEPT FOR B OUTPUTS), SO NO CURRENT FLOWS TO UART IN SHUTDOWN. B OUTPUTS INDICATE RECEIVER ACTIVITY DURING SHUTDOWN WITH EN HIGH. Figure 2. Detection of RS-232 Activity when the UART andInterface are Shut Down; Comparison of MAX3237/MAX3241(b) with Previous Transceivers (a).8
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元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
Table 1. MAX3222/MAX3237/MAX3241 Shutdown and Enable Control Truth TableSHDN0011EN0101T_OUTHigh-ZHigh-ZActiveActiveR_OUTActiveHigh-ZActiveHigh-ZR_OUTB(MAX3237/MAX3241)ActiveActiveActiveActivePower-Supply Decoupling
In most circumstances, a 0.1µF bypass capacitor isadequate. In applications that are sensitive to power-supply noise, decouple VCCto ground with a capacitorof the same value as charge-pump capacitor C1. Connectbypass capacitors as close to the IC as possible.
MAX3222/MAX3232/MAX3237/MAX3241Operation Down to 2.7V
Transmitter outputs will meet EIA/TIA-562 levels of±3.7V with supply voltages as low as 2.7V.
Transmitter Outputs when
Exiting Shutdown
Figure 3 shows two transmitter outputs when exitingshutdown mode. As they become active, the two trans-mitter outputs are shown going to opposite RS-232 lev-els (one transmitter input is high, the other is low).Each transmitter is loaded with 3kΩin parallel with2500pF. The transmitter outputs display no ringing orundesirable transients as they come out of shutdown.Note that the transmitters are enabled only when themagnitude of V- exceeds approximately 3V.
Table 2. Required Minimum Capacitor ValuesVCC(V)C1(µF)C2, C3, C4(µF)MAX3222/MAX3232/MAX32413.0 to 3.64.5 to 5.53.0 to 5.5MAX32373.0 to 3.63.15 to 3.64.5 to 5.53.0 to 5.50.220.10.0470.220.220.10.331.00.10.0470.10.10.330.47Mouse Driveability
The MAX3241 has been specifically designed to powerserial mice while operating from low-voltage power sup-plies. It has been tested with leading mouse brands frommanufacturers such as Microsoft and Logitech. TheMAX3241 successfully drove all serial mice tested andmet their respective current and voltage requirements.Figure 4a shows the transmitter output voltages underincreasing load current at 3.0V. Figure 4b shows a typicalmouse connection using the MAX3241.
5V/divT22V/divT150µs/divVCC = 3.3VC1–C4 = 0.1µFFigure 3. Transmitter Outputs when Exiting Shutdown or Powering Up
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元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241TRANSMITTER OUTPUT VOLTAGE (V)43210-1-2-3-4-5-60VCC = 3.0VT1VOUT+VOUT+T2VCCT3VOUT-VOUT-1234567LOAD CURRENT PER TRANSMITTER (mA)Figure 4a. MAX3241 Transmitter Output Voltage vs. Load Current per Transmitter
VCC = 3Vto 5.5V 0.1µF 26VCC27C3 COMPUTER SERIAL PORT3C428C124C1+C1-V+C21C2+2C2-14T1IN13T2INMAX3241 V-T1OUT9+VT2OUT10T3OUT11+V-VGNDR1IN5kΩ5kΩ5kΩ5kΩ5kΩGND25SHDNR2INR3INR4INR5IN4567MOUSE822TxVCC12T3IN2120191817161523R1OUTBR2OUTBR1OUTR2OUTR3OUTR4OUTR5OUTENFigure 4b. Mouse Driver Test Circuit10
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MAX3222-0465元器件交易网www.cecb2b.comTransceivers Using Four 0.1µF External Capacitors
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232VCCT1IN5V/div 0.1µFVCCT1OUT5V/divC1+V+C1 C3C1-R1OUT5V/divC2+MAX3222V-C2 MAX3232C4C2-MAX32375µs/divMAX3241VCC = 3.3VT_ INT_ OUTFigure 6. MAX3241 Loopback Test Result at 120kbps
R_ OUTR_ IN0VEN*5kΩ1000pFT1IN5V/divVCCSHDN*GNDT1OUT5V/div* MAX3222/MAX3241 ONLYR1OUT5V/divFigure 5. Loopback Test Circuit
2µs/divVCC = 3.3V High Data Rates
Figure 7. MAX3241 Loopback Test Result at 235kbpsThe MAX3222/MAX3232/MAX3241 maintain the RS-232±5.0V minimum transmitter output voltage even at highdata rates. Figure 5 shows a transmitter loopback testcircuit. Figure 6 shows a loopback test result at+5V120kbps, and Figure 7 shows the same test at 235kbps.0VT_INFor Figure 6, all transmitters were driven simultaneouslyat 120kbps into RS-232 loads in parallel with 1000pF.+5VFor Figure 7, a single transmitter was driven at 235kbps,0VT_OUT = R_INand all transmitters were loaded with an RS-232 receiver-5V5kΩ + 250pFin parallel with 1000pF.
+5VThe MAX3237 maintains the RS-232 ±5.0V minimumtransmitter output voltage at data rates up to 1Mbps.0VR_OUTFigure 8 shows a loopback test result at 1Mbps with150pFMBAUD = VCC. For Figure 8, all transmitters wereloaded with an RS-232 receiver in parallel with 250pF.
V = 3.3V200ns/divCCFigure 8. MAX3237 Loopback Test Result at 1000kbps(MBAUD = VCC)
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MAX3222/MAX3232/MAX3237/MAX3241元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241Interconnection with 3V and 5V Logic
The MAX3222/MAX3232/MAX3237/MAX3241 candirectly interface with various 5V logic families, includ-ing ACT and HCT CMOS. See Table 3 for more informa-tion on possible combinations of interconnections.
Table 3. Logic-Family Compatibility with Various Supply Voltages
SYSTEMPOWER-SUPPLY VOLTAGE(V)3.35MAX32_ _VCCSUPPLYVOLTAGE(V)3.35COMPATIBILITYCompatible with all CMOSfamilies.Compatible with all TTL and CMOS-logic families.Compatible with ACT andHCT CMOS, and with TTL.Incompatible with AC, HC,and CD4000 CMOS.53.3__________________________________________________Typical Operating Circuits
+3.3V0.1µF C10.1µF2C1+45 C20.1µF6C1-C2+C2-T1OUT15RS-232OUTPUTS11T2INT2OUT8TTL/CMOSINPUTS10T2INT2OUT7 17VCCV+3C3*0.1µF7C40.1µF0.1µF 0.1µF+3.3V0.1µF1C1+345C1-C2+C2-T1OUT14RS-232OUTPUTS 16VCCV+2C3*0.1µF6C40.1µFMAX3222V-MAX3232V-12T1INTTL/CMOSINPUTS11T1IN13R1OUTTTL/CMOSOUTPUTS10R2OUT1ENGND16R1IN145kΩR2IN95kΩSHDN18RS-232INPUTSTTL/CMOSOUTPUTS12R1OUTR1IN135kΩRS-232INPUTS9R2OUTR2IN85kΩGND15PIN NUMBERS REFER TO DIP/SO PACKAGES.* C3 CAN BE RETURNED TO EITHER VCC OR GROUND.SEE TABLE 2 FOR CAPACITOR SELECTION* C3 CAN BE RETURNED TO EITHER VCC OR GROUND.12______________________________________________________________________________________元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
_____________________________________Typical Operating Circuits (continued)
MAX3222/MAX3232/MAX3237/MAX3241 0.1µF 2628C1+2510.1µF 3C1-C2+C2-T1T2T3T4T5T1OUT5T2OUT6T3OUT7T4OUT1020R2OUTBT5OUT1219R1OUTR1IN45kΩR1IN85kΩLOGICOUTPUTS20R2OUTR2R2IN5kΩ18R3OUTR3R3IN115kΩ16R4OUT9RS-232INPUTSTTL/CMOSOUTPUTS18R2OUTR2IN5kΩ17R3OUTR3IN65kΩR4IN75kΩRS-232INPUTS5RS-232OUTPUTSVCCV+270.1µF40.1µF 0.1µF +3.3V0.1µF 0.1µF28C1+24C1-12C2+C2-T1OUT9T2OUT10T3OUT11 26VCCV+27C3*0.1µF 3C40.1µF 0.1µFMAX3237V-MAX3241V-24T1IN23T2INLOGICINPUTS22T3IN19T4IN17T5IN16R1OUTB14T1IN13T2IN12T3IN21R1OUTBTTL/CMOSINPUTSRS-232OUTPUTS21R1OUTR115R5OUTR5IN8MBAUD155kΩ13EN1423ENGNDSHDNGNDSHDN22225* C3 CAN BE RETURNED TO EITHER VCC OR GROUND.* C3 CAN BE RETURNED TO EITHER VCC OR GROUND.______________________________________________________________________________________13
元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241_____________________________________________Pin Configurations (continued)
TOP VIEW+EN1C1+2V+3C1-4C2+5C2-6V-7T2OUT8R2IN9R2OUT1020SHDN19VCC18GND17T1OUTC1+1V+2C1-3C2+4C2-5V-6T2OUT7R2IN8+16VCC15GND14T1OUTMAX322216R1IN15R1OUT14N.C.13T1IN12T2IN11N.C.MAX323213R1IN12R1OUT11T1IN10T2IN9R2OUTDIP/SO/TSSOPSSOP/TSSOP+C2+GNDC2-V-T1OUTT2OUTT3OUTR1INR2IN123456789+28C1+27V+26VCC25C1-C2+C2-V-R1INR2INR3INR4INR5INT1OUT12345678928C1+27V+26VCC25GNDMAX323724T1IN23T2IN22T3IN21R1OUT20R2OUT19T4IN18R3OUT17T5IN16R1OUTB15MBAUDMAX324124C1-23EN22SHDN21R1OUTB20R2OUTB19R1OUT18R2OUT17R3OUT16R4OUT15R5OUTT4OUT10R3IN11T5OUT12EN13SHDN14T2OUT10T3OUT11T3IN12T2IN13T1IN14SSOPSO/SSOP/TSSOP14______________________________________________________________________________________
元器件交易网www.cecb2b.comTransceivers Using Four 0.1µF External Capacitors
3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Ordering Information (continued)PARTTEMP RANGEPIN-PACKAGEPKGCODEPARTTEMP RANGEPIN-PACKAGEPKGCODEMAX3222EUP+-40°C to +85°C20 TSSOPU20+2MAX3232EWE+-40°C to +85°C16 Wide SOW16+1MAX3222EAP+-40°C to +85°C20 SSOPA20+1MAX3232EPE+-40°C to +85°C16 Plastic DIPP16+1MAX3222EWN+-40°C to +85°C18 SOW18+1MAX3232CAI+0°C to +70°C28 SSOPA28+2MAX3222EPN+-40°C to +85°C18 Plastic DipP18+5MAX3237EAI+-40°C to +85°C28 SSOPA28+2MAX3222C/D0°C to +70°CDice*—MAX3237CUI+0°C to +70°C28 TSSOPU28+1MAX3232CUE+0°C to +70°C16 TSSOPU16+1MAX3241CAI+0°C to +70°C28 SSOPA28+1MAX3232CSE+0°C to +70°C16 Narrow SOS16+1MAX3241CWI+0°C to +70°C28 SOW28+1MAX3232CWE+0°C to +70°C16 Wide SON16+1MAX3241EUI+-40°C to +85°C28 TSSOPU28+1MAX3232CPE+0°C to +70°C16 Plastic DIPP16+1MAX3241EAI+-40°C to +85°C28 SSOPA28+2MAX3232EUE+-40°C to +85°C16 TSSOPU16+1MAX3241EWI+-40°C to +85°C28 SOW28+1MAX3232ESE+-40°C to +85°C16 Narrow SOS16+1*+Dice are tested at TA= +25°C, DC parameters only.Denotes lead-free package.
______3V-Powered EIA/TIA-232 and EIA/TIA-562 Transceivers from Maxim
POWER-No. OFNo. OFGUAR-EIA/PARTSUPPLYRECEIVERSANTEEDVOLTAGETRANSMITTERS/ACTIVE INDATATIA-232FEATURES(V)RECEIVERSSHUTDOWNRATEOR 562(kbps)MAX2123.0 to 3.63/55120232Drives miceMAX2181.8 to 4.252/22120232Operates directly from batterieswithout a voltage regulatorMAX5622.7 to 5.253/55230562Wide supply rangeMAX5633.0 to 3.62/222305620.1µF capacitorsAutoShutdown, complementaryMAX32122.7 to 3.63/55235232receiver, drives mice, transientdetectionMAX32223.0 to 5.52/221202320.1µF capacitorsMAX32233.0 to 5.52/221202320.1µF capacitors, AutoShutdownMAX32323.0 to 5.52/2N/A1202320.1µF capacitors0.1µF capacitors, 1 complemen-MAX32373.0 to 5.55/33250/1000232tary receiver, MegaBaud operationMAX32413.0 to 5.53/551202320.1µF capacitors, 2 complemen-tary receivers, drives mice0.1µF capacitors, AutoShutdown,MAX32433.0 to 5.53/51120232complementary receiver, drives mice______________________________________________________________________________________15
MAX3222/MAX3232/MAX3237/MAX3241元器件交易网www.cecb2b.com3.0V to 5.5V, Low-Power, up to 1Mbps, True RS-232Transceivers Using Four 0.1µF External Capacitors
MAX3222/MAX3232/MAX3237/MAX3241___________________Chip Topography
MAX3222
V+C1+ENSHDNVCC___________________Chip Information
PARTMAX3222TRANSISTOR COUNT3393391212894GND C1- C2+T1OUT0.127\"(3.225mm) C2-MAX3232MAX3237MAX3241R1INV-R1OUTT2OUTR2INR2OUT0.087\"(2.209mm)T2INT1INTRANSISTOR COUNT: 339
SUBSTRATE CONNECTED TO GND
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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 www.maxim-ic.com/packages.)
TSSOP4.40mm.EPSPACKAGE OUTLINE, TSSOP 4.40mm BODY21-0066I11Revision HistoryPages changed at Rev 7: 1, 15, 16, 17
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
17__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600©2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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