UC5180C

APPLICATIONS INFORMATION

Failsafe Operation

These devices provide a failsafe operating mode to

guard against input fault conditions as defined in

EIA422A and EIA423A standards. These fault condi-

tions are (1) drive in power-off condition, (2) receiver not

interconnected with driver, (3) open-circuited intercon-

necting cable, and (4) short-circuited interconnecting

cable. If one of these four fault conditions occurs at the

inputs of a receiver, then the output of that receiver is

driven to a known logic level. The receiver is pro-

under fault conditions, while a connection to ground

mon failsafe control for four receivers.

Input Filtering (UC5180C)

The UC5180C has input filtering for additional noise re-

jection. This filtering is a function of both signal level

and frequency. For the specified input (5.5 MHz at

±500

mV) the input stage filter attenuates the signal such that

the output stage threshold levels are not exceeded and

no change of state occurs at the output.

EIA232E/V.28 / EIA423A/V.10 DATA TRANSMISSION

EIA422A/V.11 DATA TRANSMISSION

UNITRODE INTEGRATED CIRCUITS

7 CONTINENTAL BLVD.

•• MERRIMACK, NH 03054

TEL. (603) 424-2410

•• FAX (603) 424-3410

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