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a

ADM222/ADM232A/ADM242

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax:

© Analog Devices, Inc.,

High-Speed, 5 V, 0.1 F

CMOS RS-232 Drivers/Receivers

FEATURES

200 kB/s Transmission Rate

Small (0.1

F) Charge Pump Capacitors

Single 5 V Power Supply

Meets All EIA-232-E and V.28 Specifications

Two Drivers and Two Receivers

On-Board DC-DC Converters

9 V Output Swing with 5 V Supply

30 V Receiver Input Levels

Pin Compatible with MAX222/MAX232A/MAX242

APPLICATIONS

Computers

Peripherals

Modems

Printers

Instruments

FUNCTIONAL BLOCK DIAGRAM

ON EACH TTL/CMOS INPUT

ON EACH RS-232 INPUT

+5V TO +10V

VOLTAGE DOUBLER

+5V TO –10V

VOLTAGE INVERTER

C1+

C1–

V+

V–

C2+

C2–

T1

ADM2xx

T2

R1

R2

0.1 F

0.1 F

0.1 F

GND

TTL/CMOS

OUTPUTS

TTL/CMOS

INPUTS

*

RS-232

OUTPUTS

RS-232

INPUTS

**

0.1 F

5V INPUT

0.1 F

EN

SHDN

(ADM242)

(ADM222, ADM242)

GENERAL DESCRIPTION

The ADM222, ADM232A, ADM242 are a family of high-speed

RS-232 line drivers/receivers offering transmission rates up to

200 kB/s. Operating from a single 5 V power supply, a highly

efficient on-chip charge pump using small (0.1

µF) external

capacitors allows RS-232 bipolar levels to be developed. Two

RS-232 drivers and two RS-232 receivers are provided on

each device.

The devices are fabricated on BiCMOS, an advanced mixed

technology process that combines low power CMOS with high-

speed bipolar circuitry. This allows for transmission rates up to

200 kB/s, yet minimizes the quiescent power supply current to

under 5 mA.

The ADM232A is a pin-compatible, high-speed upgrade for the

AD232 and for the ADM232L. It is available in 16-lead DIP

and in both narrow and wide surface-mount (SOIC) packages.

The ADM222 contains an additional shutdown (

SHDN) func-

tion that may be used to disable the device, thereby reducing the

supply current to 0.1

µA. During shutdown, all transmit/receive

functions are disabled. The ADM222 is available in 18-lead

DIP and in a wide surface-mount (SOIC) package.

The ADM242 combines both shutdown (

SHDN) and enable

(

EN) functions. The shutdown function reduces the supply

current to 0.1 mA. During shutdown, the transmitters are dis-

abled but the receivers continue to operate normally. The

enable function allows the receiver outputs to be disabled

thereby facilitating sharing a common bus. The ADM242 is

available in 18-lead DIP and in a wide surface-mount (SOIC)

package.

781/461-3113

B

2010