Nexperia
74HC161
Presettable synchronous 4-bit binary counter; asynchronous reset
6. Functional description
Table 3. Function table[1]
Operating Input
Output
modes
MR
CP
CEP
CET
PE
Dn
Qn
TC
Reset (clear) L
X
X
X
X
X
L
L
Parallel load H
↑
X
X
l
l
L
L
H
↑
X
X
l
h
H
[2]
Count
H
↑
h
h
h
X
count
[2]
Hold
H
X
l
X
h
X
qn
[2]
(do nothing) H
X
X
l
h
X
qn
L
[1] H = HIGH voltage level
h = HIGH voltage level one set-up time prior to the LOW-to-HIGH clock transition
L = LOW voltage level
l = LOW voltage level one set-up time prior to the LOW-to-HIGH clock transition
qn = lower case letters indicate the state of the referenced output one set-up time prior to the LOW-to-HIGH clock transition
X = don’t care
↑ = LOW-to-HIGH clock transition
[2] The TC output is HIGH when CET is HIGH and the counter is at terminal count (HHHH)
0
1
2
3
4
15
5
14
6
13
7
Fig. 7. State diagram
12
11
10
9
8
aaa-012187
74HC161
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 4 — 4 October 2018
© Nexperia B.V. 2018. All rights reserved
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