1999 Sep 24

2

Philips Semiconductors

Product specification

Quad 2-input multiplexer

74AHC157;

74AHCT157

FEATURES

• ESD protection: HBM EIA/JESD22-A114-A

exceeds 2000 V MM EIA/JESD22-A115-A

exceeds 200 V CDM EIA/JESD22-C101

exceeds 1000 V

• Balanced propagation delays

• All inputs have Schmitt-trigger actions

• Multiple input enable for easy expansion

• Ideal for memory chip select decoding

• For AHC only: operates with CMOS input levels

• For AHCT only: operates with TTL input levels

• Specified from −40 to +85 and +125 °C.

FUNCTION TABLE

See note 1.

Note

1. H = HIGH voltage level;

L = LOW voltage level;

X = don’t care.

DESCRIPTION

The 74AHC/AHCT157 are high-speed Si-gate CMOS

devices and are pin compatible with low power Schottky

TTL (LSTTL). They are specified in compliance with

JEDEC standard No. 7A.

The 74AHC/AHCT157 are quad 2-input multiplexers which

select 4 bits of data from two sources under the control of

a common data select input (S). The enable input (E) is

active LOW. When E is HIGH, all of the outputs (1Y to 4Y)

are forced LOW regardless of all other input conditions.

Moving the data from two groups of registers to four

common output buses is a common use of the ‘157’. The

state of the common data select input (S) determines the

particular register from which the data comes. It can also

be used as a function generator.

The device is useful for implementing highly irregular logic

by generating any four of the 16 different functions of two

variables with one variable common.

The ‘157’ is the logic implementation of a 4-pole, 2-position

switch, where the position of the switch is determine by the

logic levels applied to S.

The logic equations are:

1Y = E

2Y = E

3Y = E

4Y = E

The ‘157’ is identical to the ‘158’ but has non-inverting

(true) outputs.

INPUT

OUTPUT

ES

nY

H

XXX

L

LLL

X

L

LL

H

X

H

LH

X

L

L

L

HXH

H

ORDERING INFORMATION

OUTSIDE NORTH

AMERICA

NORTH AMERICA

PACKAGES

PINS

PACKAGE

MATERIAL

CODE

74AHC157D

74AHC157D

16

SO

plastic

SOT109-1

74AHC157PW

74AHC157PW DH

16

TSSOP

plastic

SOT403-1

74AHCT157D

74AHCT157D

16

SO

plastic

SOT109-1

74AHCT157PW

74AHCT157PW DH

16

TSSOP

plastic

SOT403-1