PIN DESCRIPTION

PIN No

SYMBOL

NAME AND FUNCTION

1

CLOCK AB

A to B Clock Input (LOW to HIGH, Edge-Trigged)

2

SELECT AB

Select A to B Source Input

3

GAB

Direction Control Input

4, 5, 6, 7, 8, 9, 10, 11

A1 to A8

A data Inputs/Outputs

20, 19, 18, 17, 16, 15, 14, 13

B1 to B8

B Data Inputs/Outputs

21

G

Output Enable Input (Active LOW)

22

SELECT BA

Select B to A Source Input

23

CLOCK BA

B to A Clock Input (LOW to HIGH, Edge-Triggered)

12

GND

Ground (0V)

24

Positive Supply Voltage

IEC LOGIC SYMBOLS

HC646

HC648

M74HC646/648

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