TECHNICAL DATA
IN74HC640A
Octal 3-State Inverting
Bus Transceiver
High-Performance Silicon-Gate CMOS
The IN74HC640A is identical in pinout to the LS/ALS640. The
device inputs are compatible with standard CMOS outputs; with pullup
resistors, they are compatible with LS/ALSTTL outputs.
The IN74HC640A is a 3-state transceiver that is used for 2-way
asynchronous communication between data buses. The device has an
active-low Output Enable pin, which is used to place the I/O ports into
high-impedance states. The Direction control determines whether data
flows from A to B or from B to A.
ORDERING INFORMATION
IN74HC640AN Plastic
IN74HC640ADW SOIC
TA = -55° to 125° C for all packages
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Outputs Directly Interface to CMOS, NMOS, and TTL
Operating Voltage Range: 2.0 to 6.0 V
Low Input Current: 1.0 μA
High Noise Immunity Characteristic of CMOS Devices
PIN ASSIGNMENT
LOGIC DIAGRAM
FUNCTION TABLE
Control Inputs
Output
Enable
Direction
Operation
PIN 20=VCC
PIN 10 = GND
L
L
Data Transmitted
from Bus B to
Bus A (inverted)
L
H
X
Data Transmitted
from Bus A to
Bus B (inverted)
H
Buses Isolated
(High Impedance
State)
X = don’t care
Rev. 00
IKSEMICON [ IK SEMICON CO., LTD ]
