HD74BC645A Datasheet, PDF (1/9 Pages) Hitachi Semiconductor – Octal Bus Transceivers With 3 State Outputs

HD74BC645A
Octal Bus Transceivers With 3 State Outputs
ADE-205-027 (Z)
Rev.0
June 1993
Description
The HD74BC645A provides high drivability and operation equal to or better than high speed bipolar
standard logic IC by using Bi-CMOS process. The device features low power dissipation that is about 1/5
of high speed bipolar logic IC. When the frequency is 10 MHz. The device has eight bus transceivers with
three state outputs in a 20 pin package. Each device has an active low enable input (G) and a direction
control input, DiR. When DiR is high, data flows from the A inputs to the B outputs. When DiR is high,
data flows from the B inputs to the A outputs. When enable inputs (G) is high, disables both A and B ports
by placing then in a high impedance.
Features
• Input/Output are at high impedance state when power supply is off.
• Input pins can be open, when not used, owing to built in input pull up circuit.
• Input is TTL level.
• Wide operating temperature range
Ta = –40 to +85°C.
Function Table
Control Inputs
G
DIR
L
L
L
H
H
X
H : High level
L : Low level
X : Immaterial
Z : High impedance
Operation
B data to A bus
A data to B bus
Z