© 2000 Fairchild Semiconductor Corporation DS006290 www.fairchildsemi.com
April 1984
Revised March 2000
DM74AS157 • DM74AS158 Quad 1 of 2 Line Data Selector/Multiplexer
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
■ Switching specifications at 50 pF
■ Switching specifications guaranteed over full tempera-
ture and V
CC
range
■ Advanced oxide-isolated, ion-implanted Schottky TTL
process
■ Functionally and pin for pin compatible with Schottky,
low power Schottky, and advanced low power Schottky
TTL counterpart
■ Improved AC performance over Schottky, low power
Schottky, and advanced low power Schottky counter-
parts
■ Expand any data input point
■ Multiplex dual data buses
■ General four functions of two variables (one variable is
common)
■ 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
HXXX L H
LLLX L H
LLHX H L
LHXL L H
LHXH H L
