IN74ACT643

1

High-Speed Silicon-Gate CMOS

The IN74ACT643 is identical in pinout to the LS/ALS643,

HC/HCT643. The IN74ACT623 may be used as a level converter

for interfacing TTL or NMOS outputs to High Speed CMOS

inputs.

The IN74ACT643 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.

• TTL/NMOS Compatible Input Levels

• Outputs Directly Interface to CMOS, NMOS, and TTL

• Operating Voltage Range: 4.5 to 5.5 V

• Low Input Current: 1.0 µA; 0.1 µA @ 25°C

• Outputs Source/Sink 24 mA

ORDERING INFORMATION

IN74ACT643N Plastic

IN74ACT643DW SOIC

packages

PIN ASSIGNMENT

FUNCTION TABLE

Control Inputs

Output

Enable

Direction

Operation

L

L

Data

Transmitted

from Bus B to

Bus A

L

H

Data

Transmitted

from Bus A to

Bus B (inverted)

H

X

Buses

Isolated

(High

Impedance

State)

X = don’t care

LOGIC DIAGRAM

PIN 10 = GND