MAX3212EAI+ ,+2.7V to +3.6V Powered, 1µA Supply Current, 3-Driver/5-Receiver, True RS-232 TransceiverMAX3212*19-0312; Rev 0; 9/94+2.7V to +3.6V-Pow ered, 1μA Supply Current,3-Driver/5-Receiver, True R ..
MAX3218CAP ,1A Supply Current / 1.8V to 4.25V-Powered RS-232 Transceiver with AutoShutdownApplicationsBattery-Powered EquipmentSubnotebook ComputersTOP VIEWLXGND1 20PDAsINVALIDV+2 19Hand-He ..
MAX3218CAP ,1A Supply Current / 1.8V to 4.25V-Powered RS-232 Transceiver with AutoShutdownELECTRICAL CHARACTERISTICS(Circuit of Figure 1, V = 1.8V to 4.25V, C1 = 0.47µF, C2 = C3 = C4 = 1µF, ..
MAX3218CAP+ ,1µA, 1.8V to 4.25V RS-232 Transceiver with AutoShutdown™ApplicationsBattery-Powered EquipmentSubnotebook ComputersTOP VIEWLXGND1 20PDAsINVALIDV+2 19Hand-He ..
MAX3218CAP+ ,1µA, 1.8V to 4.25V RS-232 Transceiver with AutoShutdown™FeaturesThe MAX3218 RS-232 transceiver is intended for bat - BETTER THAN BIPOLAR!tery-powered EIA/T ..
MAX3218EAP ,1A Supply Current / 1.8V to 4.25V-Powered RS-232 Transceiver with AutoShutdownGeneral Description ________
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MAX6444US16K/V+T ,µP Reset Circuits with Long Manual Reset Setup PeriodApplications/V denotes an automotive qualified part. *Future product—contact factory for availabili ..
MAX6445UK23L-T ,2.313 V, mP reset circuit with long manual reset setup periodFeaturesThe MAX6443–MAX6452 low-current microprocessor Single- or Dual-Supply Voltage Monitorsrese ..
MAX6454UT29S ,uP Supervisors with Separate VCC Reset and Manual Reset OutputsFeaturesThe MAX6453–MAX6456 are low-power, dual-voltage Precision Factory-Set Reset Thresholds Fro ..
MAX6454UT46S-T ,4.625 V, mP supervisor with separate Vcc reset and manual reset outputFeaturesThe MAX6453–MAX6456 are low-power, dual-voltage Precision Factory-Set Reset Thresholds Fro ..
MAX6455UT16S+T ,µP Supervisors with Separate VCC Reset and Manual Reset OutputsApplicationsRESET 1 6 MR RESET 1 6 MR● Set-Top Boxes ● Consumer ElectronicsMAX6453 MAX6455● DVD Pla ..
MAX3212CAI+-MAX3212EAI+
+2.7V to +3.6V Powered, 1µA Supply Current, 3-Driver/5-Receiver, True RS-232 Transceiver
_______________General DescriptionThe MAX3212 uses Maxim’s new proprietary Auto-Shutdown mode to reduce supply current to 1µA. TheMAX3212, with 3 RS-232 drivers and 5 RS-232 receivers,is intended for 2.7V to 3.6V-powered EIA/TIA-232E andV.28/V.24 serial interface. True RS-232 levels are main-tained across the operating range. A guaranteed datarate of 235kbps provides compatibility with popular soft-ware for communicating with personal computers.
Supply current is reduced to 1µA with Maxim’s newAutoShutdown feature. When the MAX3212 does notsense a valid signal level on the receiver inputs, the on-board power supply and drivers shut down. This occursif the RS-232 cable is disconnected or if the transmit-ters of the connected peripheral are turned off. The sys-tem turns on again when a valid level is applied to anyRS-232 receiver input. As a result, the system savespower without changes to the existing software.
A second power-management feature is incorporated topermit automatic shutdown when the RS-232 connectionis valid but inactive. In this case, a transition detectorfacilitates shutdown when the receivers are presentedwith stationary RS-232 levels for long periods.
Three-state drivers are provided on receiver outputs sothat multiple receivers, generally of different interfacestandards, can be wire-ORed at the UART. TheMAX3212 is available in 28-pin SO and SSOP packages.
________________________ApplicationsNotebook and Palmtop Computers
Peripherals
Instruments
Battery-Powered Equipment
______________Ordering Information
____________________________Feature
BETTER THAN BIPOLAR!1µA Supply Current Using AutoShutdownOperates from Single +2.7V to +3.6V Supply28-Pin SSOP or Wide SO PackagesMeets All EIA/TIA-232E & EIA/TIA-562 SpecificationsMouse Driveability–GuaranteedLow-Cost, Surface-Mount External Components235kbps Guaranteed Data Rate–
LapLink™Compatible+5V Logic CompatibleComplementary Receiver Output Always ActiveFlow-Through Pinout2.7V to +3.6V-Powered, 1μA Supply Current-Driver/5-Receiver, True RS-232 Transceive
PARTMAX3212CWI
MAX3212CAI0°C to +70°C
0°C to +70°C
TEMP. RANGEPIN-PACKAGE28 Wide SO
28 SSOP
MAX3212EWI
MAX3212EAI-40°C to +85°C
-40°C to +85°C28 Wide SO
28 SSOP
Pin Configuration appears at end of data sheet.* ng
__________Typical Operating CircuitR1INR2INR3INR4INR5INGND
T3OUT
T2OUT
T1OUT
R1OUT
R2OUT
R3OUT
R4OUT
R5OUT
R5OUTB
T3IN
T2IN
T1IN
VCC
+3.0V
0.33µF
0.68µF1N60501N605015µH
0.33µFLNLPV-
FORCEON
TRAN
INVALID
FORCEOFF
MAX32122712164
+3.0V
+3.0V
AUTOSHUTDOWN OPERATION
FORCEOFF = HIGH, FORCEON = LOW
RS-232 PresentYes
StatusOn
Shut Down
19-0312; Rev 0; 9/94
2.7V to +3.6V-Powered, 1μA Supply Current,-Driver/5-Receiver, True RS-232 TransceiverABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= 2.7V to 3.6V, TA= TMINto TMAX, unless otherwise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.
Supply VoltagesVCC.....................................................................-0.3V to +4.6VV+............................................................(VCC- 0.3V) to +7.4VV-........................................................................-7.4V to +2.0VLN..............................................................-0.3V to (V+ + 1.0V)LP.......................................................(V- - 1.0V) to (V+ + 0.3V)Input VoltagesT_IN, EN, FORCEON, FORCEOFF.....................-0.3V to +7.0VR_IN..................................................................................±25VOutput VoltagesT_OUT...............................................................................±15VR_OUT, R5OUTB, INVALID, TRAN............-0.3V to (V+ + 0.3V)
Short-Circuit Duration, T_OUT....................................ContinuousContinuous Power Dissipation (TA= +70°C)Wide SO (derate 11.76mW/°C above +70°C)...............941mWSSOP (derate 8.00mW/°C above +70°C).....................640mWOperating Temperature RangesMAX3212C_ I.......................................................0°C to +70°CMAX3212E_ I....................................................-40°C to +85°CStorage Temperature Range.............................-65°C to +150°CLead Temperature (soldering, 10sec).............................+300°C
PARAMETERLogic Output Voltage Low
MINTYPMAXUNITS
Input Logic Threshold Low
0.3VCC
- 0.1
Logic Output Voltage High
VCC - 0.5V
Logic Output Leakage Current
Input Logic Threshold High0.67VCC
+ 0.1V
Input Current High1µA
±10µA
Input Current Low1µA
Hysteresis0.3V
Operating Voltage Range2.73.6V
CONDITIONSIOUT= 1.0mA
T_IN, EN, FORCEON, FORCEOFF
IOUT= -1.0mA
T_IN, EN, FORCEON, FORCEOFF
T_IN, EN, FORCEON, FORCEOFF
EN = GND, 0V < R_OUT < VCC
T_IN, EN, FORCEON, FORCEOFF
T_IN, VCC = 3.3V
Meets or exceeds EIA/TIA-232E specifications
3.0Receiver Input Thresholds,Transmitters Enabled
Receiver Input Thresholds,
Transmitters Disabled-0.30.3V1µA supply current, Figure 4
-3.0VFigure 4
INVALIDOutput Voltage Low
INVALIDOutput Voltage HighVCC - 0.6VIOUT= -1.0mA
Receiver Threshold to TransmittersEnabled, tWU250µsFigure 4b
0.4VIOUT= 1.0mA
Positive threshold
Negative threshold
Receiver Positive or NegativeThreshold to Invalid High, tINVH1µsFigure 4
110All R_IN unconnected, FORCEON = GND
VCCSupply Current
1.53.0mAFORCEON = FORCEOFF= VCC, no load
110µAFORCEOFF= GND
Receiver Positive or NegativeThreshold to Invalid Low, tINVL30µsFigure 4
DC CHARACTERISTICS
LOGIC INPUT AND RECEIVER OUTPUTS
AUTOSHUTDOWN(FORCEON = GND, FORCEOFF= VCC)
2.7V to +3.6V-Powered, 1μA Supply Current-Driver/5-Receiver, True RS-232 TransceiveELECTRICAL CHARACTERISTICS (continued)(VCC= 2.7V to 3.6V, TA= TMINto TMAX, unless otherwise noted.)
TIMING CHARACTERISTICS(VCC= 2.7V to 3.6V, TA= TMINto TMAX, unless otherwise noted.)
PARAMETERReceiver Propagation Delay6302000
MINTYPMAX150pF load
UNITSData Rate
Transmitter Propagation Delay8002000ns
Transmitter Output Disable Time
2500pF3kΩload
600ns
235250kbps
Transmitter Output Enable Time= 3kΩ, CL= 1000pF, one transmitterswitching, 150pF load on each receiver
250µs
SYMBOLtPLHR
tPHLT
tPLHT
tDT
tPHLR
tET
tER
tDR
Receiver Output Enable Time70200ns
Receiver Output Disable Time420700ns
CONDITIONSIncludes power-supply start-up
V/µsTransition-Region Slew RateµsEN High to TRAN Reset DelayµsEN High Pulse Width= 3kΩto 7kΩ,measured from +3V to -3V or -3V to +3V= 50pF to 2500pF= 50pF to 1000pF61330
Receiver SkewnstPHL - tPLH 40Transmitter SkewnstPHL - tPLH
EIA/TIA-232E TRANSMITTERSInput Voltage Threshold High3.0V
Input Hysteresis0.7V
Output Voltage Swing (VHIGH, VLOW)±5.0±5.5V
Output Resistance300Ω
EIA/TIA-232E Short-Circuit Current2860mA
All transmitters loaded with 3kΩto GND
VCC= V- = V+ = 0V, -2V < T_OUT < 2V
PARAMETERMINTYPMAXUNITSInput Voltage Threshold Low0.4V
Input Resistance357kΩ
CONDITIONS-15V < VIN<15V
Input Voltage Operating Range-25+25V
TIN = T2IN = GND, T3IN = VCC, T3OUT loaded with 3kΩto GND,T1OUT and T2OUT loaded with 5mATransmitter Output Voltage±5V
EIA/TIA-232E RECEIVERS
EIA/TIA-232E TRANSMITTERS
MOUSE DRIVEABILITY
2.7V to +3.6V-Powered, 1μA Supply Current,-Driver/5-Receiver, True RS-232 Transceiver__________________________________________Typical Operating Characteristics(VCC= 3.3V, TA = +25°C, unless otherwise noted.)
TRANSMITTING SUPPLY CURRENT
vs. DATA RATEMAX3212-01
DATA RATE (kbps)
(m100150200250
TRANSMITTERS LOADED
WITH 3kW + 2500pF
1 TRANSMITTER (FULL DATA RATE)
2 TRANSMITTERS (DATA RATE/8)15
TRANSMITTING SUPPLY CURRENT
vs. LOAD CAPACITANCEAX3212-02
LOAD CAPACITANCE/TRANSMITTER (pF)
235kbps
120kbps
20kbps
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX3212-03
SUPPLY VOLTAGE (V)
(m
3kW + 235kbps
3kW + 120kbps
3kW + 20kbps
3kW ONLY
SLEW RATE
vs. LOAD CAPACITANCEAX3212-04
LOAD CAPACITANCE/TRANSMITTER (pF)
(V
+SLEW
-SLEW
TRANSMITTERS LOADED
WITH 3kW AND SPECIFIED
CAPACITANCE AT 232kbps
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE AT 235kbps
MAX3212-05
LOAD CAPACITANCE/TRANSMITTER (pF)
(V
VOUT+
VOUT-
TRANSMITTERS LOADED WITH 3kW
AND SPECIFIED CAPACITANCE
TIME TO EXIT SHUTDOWN: ONE
TRANSMITTER HIGH, ONE TRANSMITTER LOWFORCEON,
FORCEOFF
VOH
T_OUT
VOL
RL = 3kW || 2500pF
100ms/div
_______________Detailed DescriptionThe MAX3212 line driver/receiver is intended for 3V-powered EIA/TIA-232E and V.28/V.24 communicationsinterfaces where 3 drivers and 5 receivers are required.The operating voltage range extends from 3.6V down to2.7V while still maintaining true RS-232 and EIA/TIA-562transmitter output voltage levels.
The circuit comprises three sections: power supply,transmitters, and receivers. The power-supply sectionconverts the supplied 3V to about ±6.5V, to providethe voltages necessary for the drivers to meet true RS-232 levels. External components are small and inex-pensive.
The transmitters and receivers are guaranteed to oper-ate at data rates of 235kbps.
The MAX3212 is equipped with Maxim’s new propri-etary AutoShutdown circuitry. This achieves a supplycurrent of 1µA by shutting down the device when theRS-232 cable is disconnected or when the connectedperipheral transmitters are turned off. While shut down,all receivers can remain active or can be disabled
under logic control. A complementary receiver remainsactive in all cases, enabling a system incorporating theMAX3212 to remain shut down and still monitor incom-ing RS-232 activity.
Three-state drivers on all receiver outputs are providedso that multiple receivers, generally of different inter-face standards, can be wire-ORed at the UART.
Switch-Mode Power SupplyThe switch-mode power supply uses a single inductorwith two inexpensive diodes and two capacitors to generate ±6.5V from the 2.7V to 3.6V input. The TypicalOperating Circuitshows the complete circuit for the pow-er supply.
Use a 15mH inductor with a saturation current rating of atleast 350mA and under 1Wresistance. Use 1N6050diodes or equivalent. Surface-mount equivalents for the1N6050 include the Motorola MMBD6050LT1, Philips PMBD6050, and Allegro (formerly Sprague) TMPD6050LT.
For C1 and C2, use ceramic capacitors with values noless than indicated in the Typical Operating Circuit.These capacitors determine the ripple on V+ and V-, but
2.7V to +3.6V-Powered, 1μA Supply Current-Driver/5-Receiver, True RS-232 Transceive
______________________________________________________________Pin Description
PINNAMEFUNCTIONLNInductor/Diode Connection PointLPInductor/Diode Connection PointVCCSupply Voltage Input, 2.7V to 3.6VENReceiver Enable Control. Drive EN low to force receiver outputs into a high-Z state. DriveEN high for normal operation. Cycle EN high then low to reset TRAN. TRAN is always lowwhen EN is high.TRANTransition Detection Output. TRAN latches high when a transition occurs on any receiverinput while EN is low. Reset by cycling the EN pin high then low.INVALIDOutput of Invalid Signal Detector. Low if invalid RS-232 levels are present on all receiver inputs, otherwise high.R5OUTBComplementary Output of R5OUT—always active
8–12R1OUT–R5OUTReceiver Outputs. Swing from GND to VCC. High-impedance when EN is low.
13, 14, 15T1IN, T2IN, T3INTransmitter InputsV-Negative Supply generated on-board
17, 18, 19T3OUT, T2OUT, T1OUTTransmitter Outputs
20–24R5IN–R1INReceiver InputsFORCEOFFDrive low to shut down transmitters and on-board power supply, overriding all automaticcircuitry and FORCEON (see Figure 3).FORCEONDrive high to overide automatic circuitry, keeping transmitters on (see Figure 3). FORCEOFF= high.V+Positive Supply generated on-boardGNDGround
not the absolute voltages. Increasing the size of C1 andC2 increases the time V+ and V- take to reach their finalvalue. Bypass VCCto GND with at least 0.33mF close tothe MAX3212. Increase this to 4.7mF if there are no otherVCCsupply bypass components less than 6 inches(15cm) away from the MAX3212.Component suppliers are listed in Table 1.
RS-232 DriversAll three drivers are identical and deliver EIA/TIA-232Eand EIA/TIA-562 output voltage levels when VCCis be-tween 2.7V and 3.6V. When FORCEOFFis driven low orwhen the AutoShutdown circuitry senses invalid voltagelevels at all receiver inputs, the drivers are disabledand the outputs are forced into a high-impedancestate.
RS-232 ReceiversThe MAX3212 receivers convert RS-232 signals toCMOS-logic output levels. All receivers have one in-verting three-state output. Receiver 5 also has a com-plementary (noninverting) output. In shutdown, all five
inverting receivers can be either active or inactiveunder logic control.
The complementary output (R5OUTB) is always active,regardless of the state of EN or the part’s shutdown sta-tus. R5OUTB can monitor RS-232 activity while theother receivers are high impedance. This allows RingIndicator to be monitored without forward biasing otherdevices connected to the receiver outputs. This is idealfor systems where the UART’s VCCis set to 0V in shut-down. (See Figure 2.)
Enable ControlThe EN input has two functions: It allows enabling/dis-abling of the receivers, and it is used to reset the transi-tion detector.
Driving EN low places five inverting receiver outputs(R_OUT) into a high-impedance state. R5OUTB isalways active, regardless of the state of EN or the part’sshutdown status (Table 2). EN has no effect on T_OUT.
EN also resets the transition detector. Drive EN high andthen low to reset the TRAN output low. TRAN goes highwhen a transition occurs on any receiver input.
2.7V to +3.6V-Powered, 1μA Supply Current,-Driver/5-Receiver, True RS-232 Transceiver
Table 1. Suggested Component Suppliers
Table 2. AutoShutdown Logic
MANUFACTURERPART NUMBERPHONEFAXMotorolaMMBD6050LT1USA (408) 749-0510USA (408) 991-7420
Murata-ErieLQH4N150K-TAUSA (404) 436-1300Japan (075) 951-9111USA (404) 684-1541Japan (075) 955-6526
SumidaCD43150USA (708) 956-0666Japan (03) 3607-5111USA (708) 956-0702Japan (03) 3607-5428
TDKNLC453232T-150KUSA (708) 803-6100Japan (03) 3278-5111USA (708) 803-6296Japan (03) 3278-5358
AllegroTMPD6050LTUSA (508) 853-5000USA (508) 853-5049
PhilipsPMBD6050USA (401) 762-3800USA (401) 767-4493
RS-232 SIGNAL
PRESENT AT
RECEIVER INPUT
FORCEOFFINPUTFORCEON
INPUTINVALIDOUTPUTTRANSCEIVER STATUSYesHXHNormal OperationHHLNormal Operation (Forced On)HLLShutdown (AutoShutdown)
YesLXHShutdown (Forced Off)LXLShutdown (Forced Off)
Diodes
Inductors
