54AC169

4-Stage Synchronous Bidirectional Counter

General Description

The ’AC/’ACT169 is fully synchronous 4-stage up/down

counter. The ’AC/’ACT169 is a modulo-16 binary counter. It

features a preset capability for programmable operation,

carry lookahead for easy cascading and a U/D input to con-

trol the direction of counting. All state changes, whether in

counting

or

parallel

loading,

are

initiated

by

the

LOW-to-HIGH transition of the Clock.

Features

n Synchronous counting and loading

n Built-In lookahead carry capability

n Presettable for programmable operation

n Outputs source/sink 24 mA

n ’ACT has TTL-compatible inputs

n Standard Microcircuit Drawing (SMD)

5962-91603

Logic Symbols

Pin

Names

Description

CEP

Count Enable Parallel Input

CET

Count Enable Trickle Input

CP

Clock Pulse Input

P

Parallel Data Inputs

PE

Parallel Enable Input

U/D

Up-Down Count Control Input

Q

Flip-Flop Outputs

TC

Terminal Count Output

DS100276-1

IEEE/IEC

DS100276-2

July 1998

© 1998 National Semiconductor Corporation

DS100276

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