Datasheet

2
Functional Diagram
OUTPUT ENABLE AND
DIRECTION-SELECT LOGIC
A0
A7
OE
DIR
B0
B7
A1
THRU
A6
B1
THRU
B6
V
CC
= 20
GND = 10
TRUTH TABLE
CONTROL INPUTS DATA PORT STATUS
OE DIR A
n
B
n
LLOI
HHZZ
HLZZ
LHIO
To prevent excess currents in the High-Z modes all I/O terminals
should be terminated with 1kΩ to 1MΩ resistors.
H = High Level
L = Low Level
I = Input
O = Output (Inversion of Input Level)
Z = High Impedance
CD54HC640, CD74HC640, CD54HCT640, CD74HCT640CD54HC640, CD74HC640, CD54HCT640, CD74HCT640