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January 2003

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FULL DUPLEX COMMUNICATIONS DEVICE

RS-422

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PROGRAMMABLE EMPHASIS INCREASES

THEDISTANCE AND DATARATE

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HIGH SPEED: DATA RATE UP TO 25Mbps

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-7V TO 7V COMON-MODE INPUT VOLTAGE

RANGE

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LVTTL LOGIC INPUT THRESHOLDS

DESCRIPTION

The ST3293 is a high-speed RS-422 transceiver

with an emphasis circuitry on the driver which

allows reliable long distance communication at

high

data

rate

by

reducing

inter

symbolic

interference. The differential amplitude of the

ST3293 is digitally programmable in 7 steps

through 3 control pins. The emphasis reduces the

inter symbolic interference by increasing the

signal amplitude under the micro control and

counteracting the effects of the cable with the

varying data stream. The ST3293 is a full duplex

device that operates from a single +5V supply. It

features driver output short circuit current limiting

and an open circuit fail-safe receiver input. The PE

input can be used as an emphasis enable. The PE

held LOW disable the emphasis instead set to

HIGH enable the emphasis with the configuration

on C0, C1 and C2 when DI change logic level. The

DI input can direct drive the outputs with a fixed

emphasis or without emphasis as shown in the

timing diagram.

ORDERING CODES

Type

Temperature

Range

Package

Comments

ST3293BD

-40 to 85 °C

SO-14 (Tube)

50 parts per tube / 20 tube per box

ST3293BDR

-40 to 85 °C

SO-14 (Tape & Reel)

2500 parts per reel

ST3293

RS-422 HIGH SPEED TRANSCEIVER

WITH DIGITAL EMPHASIS

SOP