M74HC4518

2/11

INPUT AND OUTPUT EQUIVALENT CIRCUIT

PIN DESCRIPTION

TRUTH TABLE

X : Don’t Care

Z : High Impedance

LOGIC DIAGRAM

This logic diagram has not be used to estimate propagation delays

PIN No

SYMBOL

NAME AND FUNCTION

1, 9

1CLOCK,

2CLOCK

Clock Inputs (LOW to

HIGH, Edge-Triggered)

2, 10

1ENABLE,

2ENABLE

Clock Enable Inputs

3, 4, 5, 6

1Q0 to 1Q3

Data Outputs

7, 15

1CLEAR,

2CLEAR

Asynchronous Reset

Inputs (Active LOW)

11, 12, 13,

14

2Q0 tO 2Q3 Data Outputs

8

GND

Ground (0V)

16

Vcc

Positive Supply Voltage

INPUTS

FUNCTION

CLOCK

ENABLE

CLEAR

H

L

INCREMENT COUNTER

L

L

INCREMENT COUNTER

X

L

NO CHANGE

X

L

NO CHANGE

L

L

NO CHANGE

H

L

NO CHANGE

X

X

H

Q0 THRU Q3=L