MAX3243CAI+G1Z - Maxim Integrated

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232

Transceivers with AutoShutdown

General Description

The MAX3221/MAX3223/MAX3243 achieve 1µA supply

current with Maxim’s revolutionary AutoShutdown™

feature. When the MAX3221/MAX3223/MAX3243 do not

sense a valid signal level on their receiver inputs, the

on-board power supply and drivers shut down. This

occurs if the RS-232 cable is disconnected or if the

transmitters of the connected peripheral are turned off.

The system turns on again when a valid level is applied

to any RS-232 receiver input.

The MAX3221/MAX3223/MAX3243 require only 0.1µF

capacitors in 3.3V operation, and can operate from

input voltages ranging from +3.0V to +5.5V.

A proprietary, high-efficiency, dual charge-pump power

supply and a low-dropout transmitter combine to deliv-

er true RS-232 performance from a single +3.0V to

+5.5V supply.

The MAX3221 is a 1-driver/1-receiver 16-pin SSOP

version of the 20-pin 2-driver/2-receiver MAX3223.

The MAX3243 is a 3-driver/5-receiver with a comple-

mentary always-active receiver for external monitoring

in a variety of 28 pin packages. Please see order

information table for package offerings.

Applications

•Battery-Powered Equipment

•Hand-Held Equipment

•Peripherals

•Portable Diagnostics Equipment

Benefits and Features

•Integrated Charge Pump Circuitry Simplifies Power

Requirements

•Eliminates the Need for a ±12 Supply

•Operation From a Single +3.3V or +5V Supply

•1µA Supply Current in Shutdown Mode Saves Power

•AutoShutdown Feature is Enabled After No Activity

on Receiver Inputs for 30µs

•Software Control Option for Shutdown

19-0306; Rev 9; 1/15

PART

MAX3221CAE

MAX3221EUE†-40°C to +85°C

0°C to +70°C

TEMP RANGE PIN-PACKAGE

16 SSOP

16 TSSOP

†

Future product—contact factory for availability.

AutoShutdown and UCSP are trademarks of Maxim Integrated

Products, Inc.

Pin Configurations appear at end of data sheet.

Typical Operating Circuits appear at end of data sheet.

MAX3223EPP -40°C to +85°C 20 Plastic DIP

MAX3223EAP -40°C to +85°C 20 SSOP

MAX3243CWI 0°C to +70°C 28 Wide SO

MAX3243CAI 0°C to +70°C 28 SSOP

MAX3243EWI -40°C to +85°C 28 Wide SO

MAX3243EAI -40°C to +85°C 28 SSOP

MAX3223CPP

MAX3223CAP 0°C to +70°C

0°C to +70°C 20 Plastic DIP

20 SSOP

Ordering Information

Selector Guide

MAX3221

MAX3223

MAX3243

3.0 to 5.5

3.0 to 5.55

Yes

PART Tx Rx VCC RANGE (V) AutoShutdown

MAX3221CUE†0°C to +70°C 16 TSSOP

MAX3221EAE -40°C to +85°C 16 SSOP

MAX3223CUP 0°C to +70°C 20 TSSOP

MAX3223EUP -40°C to +85°C 20 TSSOP

MAX3243CUI 0°C to +70°C 28 TSSOP

MAX3243EUI -40°C to +85°C 28 TSSOP

Maxim Integrated | 2www.maximintegrated.com

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Absolute Maximum Ratings

Electrical Characteristics

(VCC = +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional

operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to

absolute maximum rating conditions for extended periods may affect device reliability.

VCC ...........................................................................-0.3V to +6V

V+ (Note 1) ...............................................................-0.3V to +7V

V- (Note 1) ...............................................................+0.3V to -7V

V+ + |V-|(Note 1).................................................................+13V

Input Voltages

T_IN, FORCEOFF, FORCEON, EN (MAX3223) ......-0.3V to +6V

R_IN ...................................................................................±25V

Output Voltages

T_OUT.............................................................................±13.2V

R_OUT, INVALID ......................................-0.3V to (VCC + 0.3V)

Short-Circuit Duration

T_OUT ......................................................................Continuous

Continuous Power Dissipation (TA= +70°C)

16-Pin SSOP (derate 7.14mW/°C above +70°C) ...........571mW

16-Pin TSSOP (derate 6.70mW/°C above +70°C) .........533mW

20-Pin Plastic DIP (derate 11.11mW/°C above +70°C)....889mW

20-Pin SSOP (derate 8.00mW/°C above +70°C) ...........640mW

20-Pin TSSOP DIP (derate 7.00mW/°C above +70°C).....559mW

28-Pin Wide SO (derate 12.50mW/°C above +70°C) ............1W

28-Pin SSOP (derate 9.52mW/°C above +70°C) ...........762mW

28-Pin TSSOP (derate 8.70mW/°C above +70°C) .........696mW

Operating Temperature Ranges

MAX32_ _C_ _.......................................................0°C to +70°C

MAX32_ _E_ _....................................................-40°C to +85°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.

IOUT = 1.6mA

Receivers disabled

T_IN, EN, FORCEON, FORCEOFF

T_IN, FORCEON, FORCEOFF, EN (MAX3223)

IOUT = -1.0mA

CONDITIONS

VVCC - 0.6 VCC - 0.1Output Voltage High

V0.4Output Voltage Low

µA±0.05 ±10Output Leakage Current

µA±0.01 ±1.0Input Leakage Current

2.4

Input Logic Threshold High

µA1.0 10

V0.8Input Logic Threshold Low

UNITSMIN TYP MAXPARAMETER

VCC = 3.3V

VCC = 5.0V

2.0

Supply Current, AutoShutdown

Supply Current, Shutdown µA1.0 10

Supply Current,

AutoShutdown Disabled

VCC = 3.3V

or 5.0V,

TA= +25°C

mA0.3 1.0

2.7

Receiver Positive or Negative

Threshold to INVALID High (tINVH)Figure 5 µs1

Receiver Threshold to

Transmitters Enabled (tWU)Figure 5 µs250

Receiver Positive or Negative

Threshold to INVALID Low (tINVL)Figure 5 µs30

Receiver Input Thresholds to

Transmitters Enabled Figure 5 V

-2.7

INVALID Output Voltage Low IOUT = 1.6mA V0.4

Receiver Input Thresholds to

Transmitters Disabled 1µA supply current, Figure 5 V-0.3 0.3

Positive threshold

Negative threshold

INVALID Output Voltage High IOUT = -1.0mA VVCC - 0.6

DC CHARACTERISTICS

LOGIC INPUTS AND RECEIVER OUTPUTS

AUTOSHUTDOWN (FORCEON = GND, FORCEOFF = VCC)

All R_IN open, FORCEON = GND,

FORCEOFF = VCC

FORCEOFF = GND

FORCEON = FORCEOFF = VCC,

no load

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

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Electrical Characteristics (continued)

(VCC = +3.0V to +5.5V, C1–C4 = 0.1µF (Note 2), TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.)

Note 2: C1–C4 = 0.1µF, tested at 3.3V ±10%. C1 = 0.047µF, C2–C4 = 0.33µF, tested at 5.0V ±10%.

200

Normal operation 200

Receiver Output Enable Time Normal operation ns

tPLH

Receiver input to receiver output,

CL= 150pF

4 8.0 30

Transition-Region Slew Rate V/µs

VCC = 3.3V,

RL= 3kΩto 7kΩ,

TA= +25°C,

measured from +3V to

-3V or -3V to +3V

Transmitter Skew 200 ns

⏐tPHL - tPLH ⏐

PARAMETER MIN TYP MAX UNITS

±25

Output Short-Circuit Current ±35 ±60 mA

Output Resistance 300 10M Ω

Output Leakage Current µA

Input Threshold Low 0.6 1.2 V

±5.0 ±5.4Output Voltage Swing V

Maximum Data Rate 120 235 kbps

Receiver Propagation Delay 0.3 µs

CONDITIONS

VCC = V+ = V- = 0V, transmitter output = ±2V

VOUT = ±12V, VCC = 0V or 3.0V to 5.5V,

transmitters disabled

RL= 3kΩ, CL= 1000pF, one transmitter switching

All transmitter outputs loaded with 3kΩto ground

nsReceiver Output Disable Time

tPHL 0.3

Input Voltage Range -25 25 V

Input Hysteresis 0.3 V

Input Threshold High V

Input Resistance 35 7kΩTA= +25°C

0.8 1.5

1.8 2.4

1.5 2.4

TA= +25°C

VCC = 3.3V

VCC = 5.0V

CL= 200pF to 2500pF

CL= 200pF to 1000pF 630

±5Transmitter Output Voltage V

T1IN = T2IN = GND, T3IN = VCC,

T3OUT loaded with 3kΩto GND, T1OUT and

T2OUT loaded with 2.5mA each

MAX3221/MAX3223

MAX3243 200 1000

Receiver Skew 100 ns

⏐tPHL - tPLH ⏐MAX3221/MAX3223

MAX3243 100 500

RECEIVER INPUTS

TIMING CHARACTERISTICS

TRANSMITTER OUTPUTS

MOUSE DRIVEABILITY (MAX3243)

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MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Typical Operating Characteristics

(VCC = +3.3V, 235kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ, TA= +25°C, unless otherwise noted.)

-6

-5

-4

-3

-2

-1

MAX3221/MAX3223

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

MAX3221/3223-01

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

2000 30001000 4000 5000

VOUT+

VOUT-

150 500

MAX3221/MAX3223

SLEW RATE

vs. LOAD CAPACITANCE

MAX3221/3223-02

LOAD CAPACITANCE (pF)

SLEW RATE (V/μs)

2000 30001000 4000 5000

FOR DATA RATES UP TO 235kbps

+SLEW

-SLEW

MAX3221/MAX3223

SUPPLY CURRENT vs. LOAD CAPACITANCE

WHEN TRANSMITTING DATA

MAX3221/3223-03

LOAD CAPACITANCE (pF)

3 3 SU CU ( )

MAX3221 SUPPLY CURRENT (mA)

2000 30001000 4000 5000

235kbps

120kbps

20kbps

-7.5

-5.0

-2.5

2.5

5.0

7.5

MAX3243

TRANSMITTER OUTPUT VOLTAGE

vs. LOAD CAPACITANCE

MAX3221/3223-04

LOAD CAPACITANCE (pF)

TRANSMITTER OUTPUT VOLTAGE (V)

2000 30001000 4000 5000

VOUT+

1 TRANSMITTER AT 235kbps

2 TRANSMITTERS AT 30kbps

VOUT-

ALL OUTPUTS LOADED WITH 3kΩ +CL

0.1μF CHARGE-PUMP CAPACITORS

FOR ALL DATA RATES UP TO 235kbps

MAX3243

SLEW RATE

vs. LOAD CAPACITANCE

MAX3221/3223-05

LOAD CAPACITANCE (pF)

SLEW RATE (V/μs)

2000 30001000 4000 5000

+SLEW

-SLEW

MAX3243

SUPPLY CURRENT vs. LOAD

CAPACITANCE WHEN TRANSMITTING DATA

MAX3221/3223-06

LOAD CAPACITANCE (pF)

SUPPLY CURRENT (mA)

2000 30001000 4000 5000

235kbps

120kbps

20kbps

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MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Pin Description

Noninverting Receiver Output—active in shutdownR2OUTB

Output of the valid signal detector. Indicates if a valid RS-232 level is pres-

ent on receiver inputs logic “1”.

INVALID

Drive low to shut down transmitters and on-board power supply. This over-

rides all automatic circuitry and FORCEON (Table 1).

FORCEOFF

Drive high to override automatic circuitry keeping transmitters on

(FORCEOFF must be high) (Table 1).

FORCEON

Negative terminal of the voltage doubler charge-pump capacitorC1-

RS-232 Receiver InputsR_IN

RS-232 Transmitter OutputsT_OUT

TTL/CMOS Transmitter InputsT_IN

TTL/CMOS Receiver OutputsR_OUT

-5.5V generated by the charge pumpV-

Negative terminal of inverting charge-pump capacitorC2-

Positive terminal of inverting charge-pump capacitorC2+

Receiver Enable Control. Drive low for normal operation. Drive high to force

the receiver outputs into a high-Z state.

FUNCTION

GroundGND

+3.0V to +5.5V Supply VoltageVCC

LapLink is a trademark of Traveling Software.

Detailed Description

Dual Charge-Pump Voltage Converter

The MAX3221/MAX3223/MAX3243’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), regardless

of the input voltage (VCC) over the +3.0V to +5.5V

range. The charge pumps operate in a discontinuous

mode: if the output voltages are less than 5.5V, the

charge pumps are enabled; if the output voltages

exceed 5.5V, the charge pumps are disabled. Each

charge pump requires a flying capacitor (C1, C2) and

a reservoir capacitor (C3, C4) to generate the V+ and

V- supplies.

RS-232 Transmitters

The transmitters are inverting level translators that con-

vert CMOS-logic levels to 5.0V EIA/TIA-232 levels. They

guarantee a 120kbps data rate with worst-case loads of

3kΩin parallel with 1000pF, providing compatibility with

PC-to-PC communication software (such as Laplink™).

Typically, the MAX3221/MAX3223/MAX3243 can oper-

ate at data rates of 235kbps. Transmitters can be paral-

leled to drive multiple receivers or mice (MAX3243).

Figure 1 shows a complete system connection.

When FORCEOFF is driven to ground, or the Auto-

Shutdown circuitry senses invalid voltage levels at all

receiver inputs, the transmitters are disabled and the

outputs are forced into a high-impedance state.

—

NAME

MAX3221

+5.5V generated by the charge pumpV+3

Positive terminal of the voltage doubler charge-pump capacitorC1+2

—

9, 16

8, 17

12, 13

10, 15

4–8

9, 10, 11

12, 13, 14

15–19

—

MAX3223

MAX3243

228

Maxim Integrated | 6www.maximintegrated.com

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

RS-232 Receivers

The MAX3221/MAX3223/MAX3243’s receivers convert

RS-232 signals to CMOS-logic output levels. All

receivers have one inverting three-state output. In shut-

down (FORCEOFF = low) or in AutoShutdown, the

MAX3221/MAX3223’s receivers are active (Table 1).

Driving EN high places the receiver(s) in a high-imped-

ance state. The MAX3243’s receivers are high imped-

ance when the part is shut down.

The MAX3243 has an always-active complementary

output (R2OUTB). R2OUTB is an extra output that mon-

itors receiver activity while the other receivers are high

impedance. This allows Ring Indicator to be monitored

without forward biasing other devices connected to the

receiver outputs. This is ideal for systems where VCC is

set to 0V in shutdown to accommodate peripherals,

such as UARTs (Figure 2).

MAX3243

I/O

CHIP

WITH

UART

CPU

RS-232

POWER

MANAGEMENT

UNIT OR

KEYBOARD

CONTROLLER

FORCEOFF

FORCEON

INVALID

MAX3243

T1OUT

R2OUTB

5kΩ

UART

VCC

T1IN

THREE-STATED

LOGIC

TRANSITION

DETECTOR

R2IN

PROTECTION

DIODE

R2OUT

FORCEOFF = GND

VCC

μP

RS-232

UART

SHDN = GND

VCC

GND

5kΩ

(a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE

RECEIVER OUTPUT IN SHUTDOWN.

(b) NEW MAX3243: IN SHUTDOWN, R2OUTB IS USED TO MONITOR EXTERNAL

DEVICES AND R2OUT IS THREE STATED, ELIMINATING A CURRENT PATH

THROUGH THE UART'S PROTECTION DIODE.

GND

PROTECTION

DIODE

Figure 1. Interface Under Control of PMU

Figure 2. The MAX3243 detects RS-232 activity when the

UART and interface are shut down.

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

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AutoShutdown

A 1µA supply current is achieved with Maxim’s new

AutoShutdown feature, which operates when

FORCEON is low and FORCEOFF is high. When the

MAX3221/MAX3223/MAX3243 sense no valid signal

levels on all receiver inputs for 30µs, the on-board

power supply and drivers are shut off, reducing supply

current to 1µA. This occurs if the RS-232 cable is dis-

connected or the connected peripheral transmitters are

turned off. The system turns on again when a valid level

is applied to any RS-232 receiver input. As a result, the

system saves power without changes to the existing

BIOS or operating system. When using AutoShutdown,

the INVALID output is high when the device is on and

low when the device is shut down. Because INVALID

indicates the receiver inputs’ condition, it can be used

in any mode (Figure 3).

Table 2 and Figure 3c summarize the MAX3221/

MAX3223/MAX3243 operating modes. FORCEON and

FORCEOFF override the automatic circuitry and force

the transceiver into its normal operating state or into its

low-power standby state. When neither control is assert-

ed, the IC selects between these states automatically

based on receiver input levels. Figures 3a, 3b, and 5a

depict valid and invalid RS-232 receiver levels.

A mouse or other system with AutoShutdown may need

time to wake up. Figure 4 shows a circuit that forces the

transmitters on for 100ms, allowing enough time for the

other system to realize that the MAX3221/MAX3223/

Table 1a. MAX3221/MAX3223 FFOORRCCEEOOFFFFand

Enable Control Truth Table

Table 1b. MAX3243 FFOORRCCEEOOFFFFControl

Truth Table

Active*11

Active*01

FFOORRCCEEOOFFFF

High-Z10

High-Z00

T_OUT

EENN

High-Z

Active

High-Z

Active

R_OUT

+0.3V

-0.3V

INVALID

TO MAX32_ _

POWER SUPPLY

AND TRANSMITTERS

R_IN

* TRANSMITTERS ARE DISABLED, REDUCING SUPPLY CURRENT TO 1μA IF

ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR AT LEAST 30μs.

30µs

COUNTER

Active*1

High-Z0

T_OUT

FFOORRCCEEOOFFFF

Active*

High-Z

R_OUT

Active

R2OUTB

Figure 3a. MAX32_ _ Entering 1µA Supply Mode via

AutoShutdown

*Note: If the part is in AutoShutdown mode (FORCEOFF = VCC,

FORCEON = GND), it is shut down if no valid RS-232

levels are present on all receiver inputs.

FORCEON

MASTER SHDN LINE

0.1μF1MΩ

FORCEOFF

MAX3221

MAX3223

MAX3243

POWER

MANAGEMENT

UNIT

Figure 4. AutoShutdown with Initial Turn-On to Wake Up a

Mouse or Another System

+2.7V

-2.7V

INVALID

TO MAX32_ _

POWER SUPPLY

R_IN

* TRANSMITTERS ARE ENABLED IF:

ANY RECEIVER INPUT IS GREATER THAN +2.7V OR LESS THAN -2.7V.

ANY RECEIVER INPUT HAS BEEN BETWEEN +0.3V AND -0.3V FOR LESS THAN 30μs.

30µs

COUNTER

Figure 3b. MAX32_ _ with Transmitters Enabled Using

AutoShutdown

FORCEOFF POWER DOWN

INVALID

FORCEON

INVALID IS AN INTERNALLY GENERATED SIGNAL

THAT IS USED BY THE AUTOSHUTDOWN LOGIC

AND APPEARS AS AN OUTPUT OF THE DEVICE.

POWER DOWN IS ONLY AN INTERNAL SIGNAL.

IT CONTROLS THE OPERATIONAL STATUS OF

THE TRANSMITTERS AND THE POWER SUPPLIES.

Figure 3c. AutoShutdown Logic

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MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

MAX3243 is awake. If the other system outputs valid

RS-232 signals within that time, the RS-232 ports on

both systems remain enabled.

When shut down, the device’s charge pumps are turned

off, V+ decays to VCC, V- decays to ground, and the

transmitter outputs are disabled (high impedance). The

time required to exit shutdown is typically 100µs (Figure

5b).

Software-Controlled Shutdown

If direct software control is desired, INVALID can be

used to indicate DTR or Ring Indicator signal. Tie

FORCEOFF and FORCEON together to bypass Auto-

Shutdown so the line acts like a SHDN input.

Applications Information

Capacitor Selection

The capacitor type used for C1–C4 is not critical for

proper operation; either polarized or nonpolarized

capacitors may be used. The charge pump requires

0.1µF capacitors for 3.3V operation. For other supply

voltages, refer to Table 3 for required capacitor values.

Do not use values smaller than those listed in Table 3.

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 C1 without also increasing the values

of C2, C3, and C4 to maintain the proper ratios (C1

to the other capacitors).

When using the minimum required capacitor values,

make sure the capacitor value does not degrade

excessively with temperature. If in doubt, use capaci-

tors with a larger nominal value. The capacitor’s equiva-

lent series resistance (ESR) usually rises at

low temperatures and influences the amount of ripple

on V+ and V-.

Table 2. AutoShutdown Logic

RS-232 SIGNAL

PRESENT AT

RECEIVER INPUT

FFOORRCCEEOOFFFFINPUT FORCEON

INPUT IINNVVAALLIIDDOUTPUT TRANSCEIVER STATUS

Yes H X H Normal Operation

No H H L Normal Operation (Forced On)

No H L L Shutdown (AutoShutdown)

Yes L X H Shutdown (Forced Off)

No L X L Shutdown (Forced Off)

V-

VCC

V+

VCC

tINVL

tWU

INVALID

REGION

RECEIVER

INPUT

VOLTAGE

(V)

INVALID

OUTPUT

(V)

tINVH

TRANSMITTERS ENABLED, INVALID HIGH

RECEIVER INPUT LEVELS

AUTOSHUTDOWN, TRANSMITTERS DISABLED,

1μA SUPPLY CURRENT, INVALID LOW

TRANSMITTERS ENABLED, INVALID HIGH

-2.7V

-0.3V

+2.7V

+0.3V

INDETERMINATE

(b)

(a)

Figure 5. AutoShutdown Trip Levels

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

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Power-Supply Decoupling

In most circumstances a 0.1µF bypass capacitor is

adequate. In applications that are sensitive to power-

supply noise, decouple VCC to ground with a capacitor

of the same value as the charge-pump capacitor C1.

Connect bypass capacitors as close to the IC as possible.

Transmitter Outputs

when Exiting Shutdown

Figure 6 shows two transmitter outputs when exiting

shutdown mode. As they become active, the two trans-

mitter outputs are shown going to opposite RS-232

levels. Each transmitter is loaded with 3kΩin parallel

with 2500pF. The transmitter outputs display no ringing

or undesirable transients as they come out of shut-

down. Note that the transmitters are enabled only when

the magnitude of V- exceeds approximately 3V. Figure

7a shows the MAX3243’s transmitter output voltage

vs. current per transmitter. Figure 7b is a mouse driver

test circuit.

Mouse Driveability (MAX3243)

The MAX3243 has been specifically designed to power

serial mice while operating from low-voltage power sup-

plies. It has been tested with samples of ten major mouse

models from six manufacturers including the leading

three: Logitech (5 models), Mouse Systems, and

Microsoft. The MAX3243 successfully drove all serial

mice and met their respective current and voltage

requirements. Figure 7a shows the transmitter outputs

under increasing load current. The MAX3243’s switching

regulator ensures the transmitters will supply at least ±5V

during worst-case conditions. The AutoShutdown feature

does not work with a mouse, so FORCEOFF and

FORCEON should be connected to VCC.

High Data Rates

The MAX3221/MAX3223/MAX3243 maintain the RS-232

±5.0V minimum transmitter output voltage even at high

data rates. Figure 8 shows a transmitter loopback test

circuit. Figure 9 shows a loopback test result at

120kbps, and Figure 10 shows the same test at

235kbps. For Figure 9, all three transmitters were driv-

en simultaneously at 120kbps into RS-232 loads in par-

allel with 1000pF. For Figure 10, a single transmitter

was driven at 235kbps, but all three transmitters were

loaded with an RS-232 receiver in parallel with 1000pF.

Interconnection with 3V and 5V Logic

The MAX3221/MAX3223/MAX3243 can directly inter-

face with various 5V logic families, including ACT and

HCT CMOS. See Table 4 for more information on possi-

ble combinations of interconnections.

-6

-5

-4

-3

-2

-1

01234567

MAX32

LOAD CURRENT PER TRANSMITTER (mA)

TRANSMITTER OUTPUT VOLTAGE (V)

VOUT+

VCC = 3.0V

VOUT-

VOUT+

VCC VOUT-

Figure 7a. MAX3243 Transmitter Output Voltage vs. Load

Current per Transmitter

5V/div

VCC = +3.3V

C1–C4 = 0.1μF

2V/div

50μs/div

Figure 6. Transmitter Outputs when Exiting Shutdown or

Powering Up

Maxim Integrated | 10www.maximintegrated.com

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

COMPUTER SERIAL PORT

-V

GND

SERIAL

MOUSE

MAX3243

FORCEOFF

R5OUT

R4OUT

R3OUT

R2OUT

R1OUT

R2OUTB

LOGIC

OUTPUTS

5kΩ

R5IN 8

R4IN 7

R3IN 6

R2IN 5

R1IN 4

RS-232

INPUTS

GND

LOGIC

INPUTS

T3IN

T2IN

T1IN

C2-

C2+

C1-

C1+

T3OUT 11

T2OUT 10

T1OUT 9

V-

V+

VCC

0.1μF

0.1μF 26

0.1μF

FORCEON

INVALID

TO POWER

MANAGEMENT

UNIT

+3.3V

Figure 7b. Mouse Driver Test Circuit

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Maxim Integrated | 11www.maximintegrated.com

Figure 10. Loopback Test Result at 235kbps

T1IN

R1OUT

VCC = +3.3V, 235kbps

C1–C4 = 0.1μF

T1OUT

5V/div

2μs/div

5V/div

MAX3221

MAX3223

MAX3243

5kΩ

R_ IN

R_ OUT

EN (MAX3221/3)

C2-

C2+

C1-

C1+

V-

V+

VCC

0.1μF

VCC

FORCEOFF

T_ OUT

T_ IN

GND

VCC

0V 1000pF

Figure 8. Loopback Test Circuit

Figure 9. Loopback Test Result at 120kbps

T1IN

R1OUT

VCC = +3.3V, 120kbps

C1–C4 = 0.1μF

T1OUT

5V/div

5μs/div

Table 4. Logic Family Compatibility with

Various Supply Voltages

Table 3. Required Capacitor Values

VCC SUPPLY

VOLTAGE

(V)

COMPATIBILITY

3.3 3.3 Compatible with all CMOS

families.

5 5 Compatible with all TTL and

CMOS-logic families.

SYSTEM

POWER-

SUPPLY

VOLTAGE

(V)

53.3

Compatible with ACT and

HCT CMOS, and with TTL.

Incompatible with AC, HC,

or CD4000 CMOS.

VCC

(V)

(µF)

C2, C3, C4

(µF)

3.0 to 3.6 0.1 0.1

4.5 to 5.5 0.047 0.33

3.0 to 5.5 0.1 0.47

Maxim Integrated | 12www.maximintegrated.com

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Typical Operating Circuits

MAX3221

FORCEON

R1OUT9

FORCEOFF 16

INVALID 10

GND

T1IN

C2-

C2+

C1-

C1+

R1IN 8

T1OUT 13

V- 7

V+ 3

VCC

0.1μF

0.1μF 15

0.1μF

+3.3V

TO POWER

MANAGEMENT

UNIT

5kΩ

MAX3223

FORCEON

R2OUT10

R1OUT15

FORCEOFF 20

INVALID 11

R2IN 9

GND

RS-232

OUTPUTS

TTL/CMOS

INPUTS T2IN

T1IN

C2-

C2+

C1-

C1+

R1IN 16

T2OUT 8

T1OUT 17

V- 7

V+ 3

VCC

0.1μF

0.1μF 19

0.1μF

+3.3V

RS-232

INPUTS

TO POWER

MANAGEMENT

UNIT

TTL/CMOS

OUTPUTS 5kΩ

5kΩ

MAX3243

FORCEOFF

R5OUT

R4OUT

R3OUT

R2OUT

R1OUT

R2OUTB

LOGIC

OUTPUTS

5kΩ

R5IN 8

R4IN 7

R3IN 6

R2IN 5

R1IN 4

RS-232

INPUTS

GND

RS-232

OUTPUTS

LOGIC

INPUTS

T3IN

T2IN

T1IN

C2-

C2+

C1-

C1+

T3OUT 11

T2OUT 10

T1OUT 9

V- 3

V+ 27

VCC

0.1μF

0.1μF 26

0.1μF

FORCEON

INVALID

TO POWER

MANAGEMENT UNIT

+3.3V

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Maxim Integrated | 13www.maximintegrated.com

3V-Powered EIA/TIA-232 and EIA/TIA-562 Transceivers from Maxim

0.1µF capacitors, MAX242 pinout23212022/23.0 to 5.5MAX3222

0.1µF capacitors, AutoShutdown23212022/23.0 to 5.5MAX3223

0.1µF capacitors, AutoShutdown

complementary receiver,

drives mice

23212013/53.0 to 5.5MAX3243

0.1µF capacitors, MAX232 pinout232120N/A2/23.0 to 5.5MAX3232

0.1µF capacitors, 16-pin SSOP23212011/13.0 to 5.5MAX3221

232

562

232

562

232

EIA/TIA-

232

OR 562

2.7 to 3.6

AutoShutdown, complementary

receiver, drives mice, transient

detection

23553/5MAX3212

0.1µF capacitors12022/23.0 to 3.6MAX563

Operates directly from batteries

without a voltage regulator

12022/21.8 to 4.25MAX218

No. OF

RECEIVERS

ACTIVE IN

SHUTDOWN

POWER-

SUPPLY

VOLTAGE

(V)

230kbps guaranteed data rate23053/52.7 to 5.25MAX562

Drives mice12053/53.0 to 3.6MAX212

FEATURES

GUAR-

ANTEED

DATA

RATE

(kbps)

No. OF

TRANSMITTERS/

RECEIVERS

PART

0.1µF capacitors, 2 complemen-

tary receivers, drives mice

23212053/53.0 to 5.5MAX3241

Maxim Integrated | 14www.maximintegrated.com

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Pin Configurations

FORCEOFF

VCC

GND

T1OUT

C1-

V+

C1+

R1IN

R1OUT

FORCEON

T1IN

T2OUT

V-

C2-

C2+

T2IN

INVALID

R2OUT

R2IN

DIP/SSOP/TSSOP

MAX3223

C1+

V+

VCC

GND

C1-

FORCEON

FORCEOFF

INVALID

R2OUTB

R1OUT

R2OUT

R3OUT

R4OUT

R5OUT

C2+

C2-

V-

R1IN

R2IN

R3IN

R4IN

R5IN

T1OUT

T2OUT

T3OUT

T3IN

T2IN

T1IN

SO/SSOP/TSSOP

MAX3243

TOP VIEW

C1+

V+

C1-

C2+

C2-

V-

R1IN

FORCEOFF

VCC

GND

T1OUT

FORCEON

T1IN

INVALID

R1OUT

MAX3221

SSOP/TSSOP

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Maxim Integrated | 15www.maximintegrated.com

SSOP.EPS

PACKAGE OUTLINE, SSOP, 5.3 MM

21-0056 C

REV.DOCUMENT CONTROL NO.APPROVAL

PROPRIETARY INFORMATION

TITLE:

NOTES:

1. D&E DO NOT INCLUDE MOLD FLASH.

2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED .15 MM (.006").

3. CONTROLLING DIMENSION: MILLIMETERS.

4. MEETS JEDEC MO150.

5. LEADS TO BE COPLANAR WITHIN 0.10 MM.

7.90

0∞

0.301

0.025

8∞

0.311

0.037

0∞

7.65

0.63

8∞

0.95

MAX

5.38

MILLIMETERS

DIM

SEE VARIATIONS

0.0256 BSC

0.010

0.004

0.205

0.002

0.015

0.008

0.212

0.008

INCHES

MIN MAX

0.078

0.65 BSC

0.25

0.09

5.20

0.05

0.38

0.20

0.21

MIN

1.73 1.99

MILLIMETERS

6.07

10.07

8.07

7.07

INCHES

0.239

0.397

0.317

0.278

MIN

0.249

0.407

0.328

0.289

MAX MIN

6.33

10.33

8.33

7.33

14L

16L

28L

24L

20L

MAX N

eA1 L

0.068

TSSOP4.40mm.EPS

Package Information

For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or

“-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the

package regardless of RoHS status.

Maxim Integrated | 16www.maximintegrated.com

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

SOICW.EPS

PACKAGE OUTLINE, .300" SOIC

21-0042 B

REV.DOCUMENT CONTROL NO.APPROVAL

PROPRIETARY INFORMATION

TITLE:

TOP VIEW

FRONT VIEW

MAX

0.012

0.104

0.019

0.299

0.013

INCHES

0.291

0.009

DIM

0.014

0.004

MIN

0.093A

0.23

7.40 7.60

0.32

MILLIMETERS

0.10

0.35

2.35

MIN

0.49

0.30

MAX

2.65

0.050

0.016L0.40 1.27

0.5120.496D

MINDIM

INCHES

MAX

12.60 13.00

MILLIMETERS

MIN MAX

20 AC

0.447 0.463 AB11.7511.35 18

0.398 0.413 AA10.5010.10 16

N MS013

SIDE VIEW

H 0.4190.394 10.00 10.65

e 0.050 1.27

D 0.6140.598 15.20 2415.60 AD

D 0.7130.697 17.70 2818.10 AE

0∞-8∞

VARIATIONS:

PDIPN.EPS

Package Information (continued)

For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or

“-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the

package regardless of RoHS status.

Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent

licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and

max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.

MAX3221/MAX3223/MAX3243 +3V to +5.5V RS-232 Transceivers

with AutoShutdown

Revision History

REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

9 1/15 Updated General Description and Benefits and Features sections 1