TLF9169

PRELIMINARY

April 1987

DM54ALS390DM74ALS390 Dual 4-Bit Decade Counters

General Description

Each of these monolithic counters contains eight master-

slave flip-flops and additional gating to implement two inde-

pendent four bit counters in a single package

To use their maximum count length the B input is connect-

ed to the QA output The input count pulses are applied to

input A and the outputs are as described in the appropriate

truth table A symmetrical divide-by-ten count can be ob-

tained by connecting the QD output to the A input and ap-

plying the input count to the B input

Features

Y

Switching specifications at 50 pF

Y

Switching specifications guaranteed over full tempera-

Y

Advanced oxide-isolated

ion-implanted Schottky TTL

process

Y

Individual clocks for A and B flip-flops provide dual di-

vide-by-2 and divide-by-5 counters

Y

Direct clear for each 4-bit counter

Connection Diagram

TLF9169 – 1

Order Number DM54ALS390J DM74ALS390M or

DM74ALS390N

See NS Package Number J16A M16A or N16A

Function Tables

BCD Count Sequence

(See Note 2)

Count

Output

QD

QC

QB

QA

0L

L

L

L

1L

L

L

H

2L

L

H

L

3L

L

H

H

4L

H

L

L

5L

H

L

H

6L

H

H

L

7L

H

H

H

8H

L

L

L

9H

L

L

H

Bi-Quinary (5-2)

(See Note 3)

Count

Output

QA

QD

QC

QB

0L

L

L

L

1L

L

L

H

2L

L

H

L

3L

L

H

H

4L

H

L

L

5H

L

L

L

6H

L

L

H

7H

L

H

L

8H

L

H

H

9H

H

L

L

Note 2

Output QA is connected to input B for BCD count

Note 3

Output QD is connected to input A for bi-quinary count

This document contains information on a product under development NSC reserves the right to change or discontinue this product without notice

C1995 National Semiconductor Corporation

RRD-B30M105Printed in U S A