MC74AC161 Datasheet, PDF (1/12 Pages) ON Semiconductor – Synchronous Presettable Binary Counter

Synchronous Presettable
Binary Counter
The MC74AC161/74ACT161 and MC74AC163/74ACT163 are high-speed
synchronous modulo-16 binary counters. They are synchronously presettable for
application in programmable dividers and have two types of Count Enable inputs
plus a Terminal Count output for versatility in forming synchronous multistage
counters. The MC74AC161/74ACT161 has an asynchronous Master Reset input
that overrides all other inputs and forces the outputs LOW. The MC74AC163/
74ACT163 has a Synchronous Reset input that overrides counting and parallel
loading and allows the outputs to be simultaneously reset on the rising edge of
the clock.
• Synchronous Counting and Loading
• High-Speed Synchronous Expansion
• Typical Count Rate of 125 MHz
• Outputs Source/Sink 24 mA
• ′ACT161 and ′ACT163 Have TTL Compatible Inputs
VCC TC Q0 Q1 Q2 Q3 CET PE
16 15 14 13 12 11 10 9
MC74AC161
MC74ACT161
MC74AC163
MC74ACT163
SYNCHRONOUS
PRESETTABLE
BINARY COUNTER
N SUFFIX
CASE 648-08
PLASTIC
D SUFFIX
CASE 751B-05
PLASTIC
12345678
*R CP P0 P1 P2 P3 CEP GND
PIN NAMES
CEP
CET
CP
MR
SR
P0–P3
PE
Q0–Q3
TC
Count Enable Parallel Input
Count Enable Trickle Input
Clock Pulse Input
(′161) Asynchronous Master Reset Input
(′163) Synchronous Reset Input
Parallel Data Inputs
Parallel Enable Input
Flip-Flop Outputs
Terminal Count Output
LOGIC SYMBOL
PE P0 P1 P2 P3
CEP
CET
TC
CP
*R Q0 Q1 Q2 Q3
*MR for ′161
*SR for ′163
FACT DATA
5-1