TECHNICAL DATA

KK74AC257

Quad 2-Input Data Selector/Multiplexer

with 3-State Outputs

High-Speed Silicon-Gate CMOS

ORDERING INFORMATION

KK74AC257N Plastic

KK74AC257D SOIC

The

KK74AC257

is

identical

in

pinout

to

the

LS/ALS257,

HC/HCT257. The device inputs are compatible with standard CMOS

outputs; with pullup resistors, they are compatible with LS/ALS 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.

• Outputs Directly Interface to CMOS, NMOS, and TTL

• Operating Voltage Range: 2.0 to 6.0 V

• Low Input Current: 1.0 µA; 0.1 µA @ 25°C

• High Noise Immunity Characteristic of CMOS Devices

• Output Source/Sink 24 mA

PIN ASSIGNMENT

LOGIC DIAGRAM

PIN 8 = GND

FUNCTION TABLE

Inputs

Outputs

Output

Enable

Select

Y0-Y3

H

X

Z

L

L

A0-A3

L

H

B0-B3

X=don’t care

Z = high-impedance state

A0-A3,B0-B3=the levels of the respective

Nibble Inputs

1