© 2000 Fairchild Semiconductor Corporation

DS006290

www.fairchildsemi.com

April 1984

Revised March 2000

DM74AS157 • DM74AS158

Quad 1 of 2 Line Data Selector/Multiplexer

General Description

These data selectors/multiplexers contain inverters and

drivers to supply full on-chip data selection to the four out-

put gates. A separate STROBE input is provided. A 4-bit

word is selected from one of two sources and is routed to

the four outputs. The AS157 presents true data whereas

the AS158 presents inverted data to minimize propagation

delay time.

Features

s Switching specifications at 50 pF

s Switching specifications guaranteed over full tempera-

s Advanced oxide-isolated, ion-implanted Schottky TTL

process

s Functionally and pin for pin compatible with Schottky,

low power Schottky, and advanced low power Schottky

TTL counterpart

s Improved AC performance over Schottky, low power

Schottky, and advanced low power Schottky counter-

parts

s Expand any data input point

s Multiplex dual data buses

s General four functions of two variables (one variable is

common)

s Source programmable counters

Ordering Code:

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Connection Diagram

Function Table

H

= HIGH Level

L

= LOW Level

X

= Don't Care

Order Number

Package Number

Package Description

DM74AS157M

M16A

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

DM74AS157SJX

M16D

16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide

DM74AS157N

N16E

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

DM74AS158M

M16A

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

DM74AS158N

N16E

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

Inputs

Output Y

STROBE Select

A

B

DM74AS157 DM74AS158

HX

X

X

L

H

LL

L

X

L

H

LL

H

X

H

L

LH

X

L

L

H

LH

X

H

H

L