HD74HC257
Quad. 2-to-1-line Data Selectors/Multiplexers
(with noninverted 3-state outputs)
Description
The large output drive capability coupled with the 3-state feature make this device ideal for interfacing with
bus lines in a bus organized system. When the output control input line is taken high, the outputs of all four
multiplexers are sent into a high impedance state. When the output control line is low, the select input
chooses whether the A or B input is used.
Features
•
High Speed Operation: t
pd
(Data to Y) = 10.5 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
Inputs
Output Control
L
L
L
L
H
Select
L
L
H
H
X
A
L
H
X
X
X
B
X
X
L
H
X
Outputs
Y
L
H
L
H
High impedance
Notes H: high level, L: low level, X: irrelevant
HITACHI [ HITACHI SEMICONDUCTOR ]
