SP3495E-3497E

HIGH SPEED +3.3V RS-485/RS-422 TRANSCEIVERS WITH +/-15KV ESD PROTECTION AND

ADVANCED FAILSAFE

MAY 2009

REV. 1.0.0

GENERAL DESCRIPTION

The SP3495E - SP3497E transceivers are suitable

for

high

speed

bidirectional

communication

on

multipoint bus transmission lines. They are designed

for balanced data transmission and comply with both

RS-485 and RS-422 EIA standards. Each device

contains one differential driver and one differential

receiver

Driver differential outputs and receiver differential

inputs are connected internally to form a half-duplex

input/output to the RS-485 bus. Separate RE and DE

pins enable and disable the driver and receiver

independently or may be

externally connected

together as a direct control. The device enters a low

power shutdown mode if both driver and receiver are

disabled. the bus-pin outputs of disabled or powered

down devices are in high impedance state. The high

impedance driver output is maintained over the entire

common-mode voltage range of -7V to +12V.

SP3495E - SP3497E operates from a single 3.3V

power supply. SP3495E - SP3497E transceivers load

the data bus only half as much as a standard RS-485

unit load. This allows up to 64 devices to be

connected simultaneously on a bus without violating

required RS-485 signal margin and without using

repeaters. Excessive power dissipation caused by

bus contention or by shorting outputs to ground or a

voltage source is prevented by short circuit protection

and thermal shutdown. This feature forces the driver

output into high impedance state if the absolute value

of the output current exceeds 250mA or if junction

temperature exceeds 165°C. Receivers will fail-safe

to a logic high output state if the inputs are

unconnected (floating) or shorted. All RS-485 inputs

and outputs are ESD protected up to +/-15kV Human

Body Model.

FEATURES

shutdown for overload protection

TYPICAL APPLICATIONS