January 1995

3

Philips Semiconductors

Product specification

24-stage frequency divider and oscillator

HEF4521B

MSI

HEF4521BP(N): 16-lead DIL; plastic (SOT38-1)

HEF4521BD(F): 16-lead DIL; ceramic (cerdip) (SOT74)

HEF4521BT(D): 16-lead SO; plastic (SOT109-1)

( ): Package Designator North America

Fig.2 Pinning diagram.

COUNT CAPACITY

OUTPUT

COUNT CAPACITY

FUNCTIONAL TEST SEQUENCE

INPUTS

CONTROL

TERMINALS

OUTPUTS

REMARKS

MR

HL

L

L

counter is in three 8-stage sections

counter is reset by MR

H

(the counter advances on the LOW

to HIGH transition)

LL

L

LH

L

H

LH

L

now made floating and becomes an

output; the device is now in the

L

counter ripples from an all HIGH

state to an all LOW state

A test function has been included for the reduction of the

test time required to exercise all 24 counter stages. This

test function divides the counter into three 8-stage

the 8-stage sections in parallel. All flip-flops are now at a

HIGH state.

The counter is now returned to the normal 24-stage in

cause the counter to ripple from an all HIGH state to an all

LOW state.