74LVC169_5

© NXP B.V. 2009. All rights reserved.

Product data sheet

Rev. 05 — 8 June 2009

6 of 22

NXP Semiconductors

74LVC169

Presettable synchronous 4-bit up/down binary counter

6.

Functional description

[1]

H = HIGH voltage level steady state

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

L = LOW voltage level steady state

l = LOW voltage level one set-up time prior to the LOW-to-HIGH clock transition

qn = Lower case letters indicate state of referenced output prior to the LOW-to-HIGH clock transition

X = don’t care

↑ = LOW-to-HIGH clock transition

* = The TC is LOW when CET is LOW and the counter is at terminal count

Terminal count up is (HHHH) and terminal count down is (LLLL)

Table 3.

Function table[1]

Operating modes

Input

Output

CP

U/D

CEP

CET

PE

Dn

Qn

TC

Parallel load (Dn to Qn)

↑

XXXI

I

L

*

↑

XXXl

h

H

*

Count up (increment)

↑

h

I

I

h

X

count up

*

Count down (decrement)

↑

IIIh

X

count down

*

Hold (do nothing)

↑

Xh

Xh

Xqn

*

↑

XXXh

Xqn

H

Fig 6.

State diagram

001aaa647

0

15

14

13

12

1

2

3

4

5

6

7

11

count down

count up

10

9

8