TECHNICAL DATA
IN74HC257A
Quad 2-Input Data Selector/Multiplexer
with 3-State Outputs
High-Performance Silicon-Gate CMOS
The IN74HC257A is identical in pinout to the LS/ALS257. The
device inputs are compatible with standard CMOS outputs; with pullup
resistors, they are compatible with LS/ALSTTL outputs.
This device selects a (4-bit) nibble from either the A or B inputs as
determined by the Select input. The nibble is presented at the outputs in
noninverted from when the Output Enable pin is at a low level. A high
level on the Output Enable pin switches the outputs into the high-
impedance state.
ORDERING INFORMATION
IN74HC257AN Plastic
IN74HC257AD SOIC
TA = -55° to 125° C for all packages
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Outputs Directly Interface to CMOS, NMOS, and TTL
Operating Voltage Range: 2.0 to 6.0 V
Low Input Current: 1.0 µA
High Noise Immunity Characteristic of CMOS Devices
PIN ASSIGNMENT
LOGIC DIAGRAM
FUNCTION TABLE
Inputs
Output
Outputs
Y0-Y3
Select
Enable
H
X
L
Z
L
L
A0-A3
B0-B3
PIN 16 =VCC
PIN 8 = GND
H
X=don’t care
Z = high-impedance state
A0-A3,B0-B3=the levels of the respective
Nibble Inputs
Rev. 00
IKSEMICON [ IK SEMICON CO., LTD ]
