HD74HCT449 Datasheet, PDF (1/8 Pages) Hitachi Semiconductor – Quad. Bus Transceivers with Individual Direction Controls

HD74HCT449
Quad. Bus Transceivers with Individual Direction Controls
Description
The HD74HCT449 has 4 bus transceivers. The device has direction control inputs with individual. And
this control inputs select data transmissible direction.
When GBA is high, A outputs are disable, and when GAB is high, B outputs are disable.
Features
• LSTTL Output Logic Level Compatibility as well as CMOS Output Compatibility
• High Speed Operation: t_pd (A to B) = 12.5 ns typ (C_L = 50 pF)
• High Output Current: Fanout of 15 LSTTL Loads
• Wide Operating Voltage: V_CC = 4.5 to 5.5 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: I_CC (static) = 4 µA max (Ta = 25°C)
Function Table
Enable
GBA
H
X
L
X
H
H : High Level
L : Low Level
X : Irrelevant.
GAB
H
L
X
H
X
Direction DIR
X
H
L
H
L
Operation
Isolation
A data to B bus
B data to A bus
Isolation
Isolation