December 1990

4

Philips Semiconductors

Product specification

Presettable synchronous 4-bit binary

counter; asynchronous reset

74HC/HCT161

FUNCTION TABLE

Note

1. The TC output is HIGH when CET is HIGH and the counter is at terminal count (HHHH).

H = HIGH voltage level

h = HIGH voltage level one set-up time prior to the LOW-to-HIGH CP transition

L = LOW voltage level

I = LOW voltage level one set-up time prior to the LOW-to-HIGH CP transition

q = lower case letters indicate the state of the referenced output one set-up time prior to the

LOW-to-HIGH CP transition

X = don’t care

↑ = LOW-to-HIGH CP transition

OPERATING MODE

INPUTS

OUTPUTS

MR

CP

CEP

CET

PE

TC

reset (clear)

L

X

X

X

X

X

L

L

parallel load

H

H

↑

↑

X

X

X

X

I

I

I

h

L

H

L

(1)

count

H

↑

h

h

h

X

count

(1)

hold

(do nothing)

H

H

X

X

I

X

X

I

h

h

X

X

(1)

L

Fig.4 Functional diagram.