TECHNICAL DATA
IN74AC643
Octal 3-State Bus Transceiver
High-Speed Silicon-Gate CMOS
The IN74AC643 is identical in pinout to the LS/ALS643,
HC/HCT643. The device inputs are compatible with standard CMOS
outputs; with pullup resistors, they are compatible with LS/ALS outputs.
The IN74AC643 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.
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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; o.1 μA @ 25°C
High Noise Immunity Characteristic of CMOS Devices
Outputs Source/Sink 24 mA
ORDERING INFORMATION
IN74AC643N Plastic
IN74AC643DW SOIC
TA = -40° to 85° C for all packages
PIN ASSIGNMENT
LOGIC DIAGRAM
FUNCTION TABLE
Control Inputs
Output
Direction
Operation
Enable
L
L
Data Transmitted
from Bus B to
Bus A
PIN 20=VCC
PIN 10 = GND
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 ]
