HD74HC640 Datasheet, PDF (1/11 Pages) Hitachi Semiconductor – Octal Bus Transceivers (with 3-state outputs)

HD74HC640/HD74HC643
Octal Bus Transceivers (with 3-state outputs)
Description
Each device has an active enable G and a direction control input, DIR. when DIR is high, data flows from
the A inputs to the B outputs. When DIR is low, data flows from the B inputs to the A outputs. The
HD74HC640 transfers inverted data from one bus to other and the HD74HC643 transfers inverted data
from the A bus to the B bus and true data from the B bus to the A bus.
Features
• High Speed Operation: t_pd = 12 ns typ (C_L = 50 pF)
• High Output Current: Fanout of 15 LSTTL Loads
• Wide Operating Voltage: V_CC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: I_CC (static) = 4 µA max (Ta = 25°C)
Function Table
Control Inputs
G
DIR
L
L
L
H
H
X
Operation
HD74HC640
B data to A bus
A data to B bus
Isolation
HD74HC643
B data to A bus
A data to B bus
Isolation