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 A max
Low Quiescent Supply Current: I
CC
(static) = 4 A max (Ta = 25C)
Function Table
Enable
G
BA
G
AB
Direction DIR
Operation
H
H
X
Isolation
X
L
H
A data to B bus
L
X
L
B data to A bus
X
H
H
Isolation
H
X
L
Isolation
H :
High Level
L
:
Low Level
X :
Irrelevant.
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