Dual 4-Bit Decade Counters - National Semiconductor
Description
DM54ALS390 DM74ALS390 Dual 4-Bit Decade Counters
PRELIMINARY
April 1987
DM54ALS390 DM74ALS390 Dual 4-Bit Decade Counters
General Description
Each of these monolithic counters contains eight masterslave flip-flops and additional gating to implement two independent four bit counters in a single package To use their maximum count length the B input is connected 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 obtained by connecting the QD output to the A input and applying the input count to the B input
Features
Y Y
Y
Y
Y
Switching specifications at 50 pF Switching specifications guaranteed over full temperature and VCC range Advanced oxide-isolated ion-implanted Schottky TTL process Individual clocks for A and B flip-flops provide dual divide-by-2 and divide-by-5 counters Direct clear for each 4-bit counter
Connection Diagram
Function Tables
BCD Count Sequence (See Note 2) Count QD 0 1 2 3 4 5
TL F 9169 – 1
Output QC L L L L H H H H L L QB L L H H L L H H L L QA L H L H L H L H L H L L L L L L L L H H
6 7 8 9
Order Number DM54ALS390J DM74ALS390M or DM74ALS390N See NS Package Number J16A M16A or N16A
Bi-Quinary (5-2) (See Note 3) Count QA 0 1 2 3 4 5 6 7 8 9 L L L L L H H H H H Output QD L L L L H L L L L H QC L L H H L L L H H L QB L H L H L L H L H 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 H e High Logic Level L e Low Logic Level
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 TL F 9169 RRD-B30M105 Printed in U S A
Free Datasheet http://www.
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