Datasheet

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
SDAS081C − APRIL 1982 − REVISED DECEMBER 1994
Copyright  1994, Texas Instruments Incorporated
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
POST OFFICE BOX 1443 • HOUSTON, TEXAS 77251−1443
• Buffered Inputs and Outputs
• Package Options Include Plastic
Small-Outline (D) Packages, Ceramic Chip
Carriers (FK), and Standard Plastic (N) and
Ceramic (J) 300-mil DIPs
description
These data selectors/multiplexers contain
inverters and drivers to supply full data selection
to the four output gates. A separate strobe (G
)
input is provided. A 4-bit word is selected from one
of two sources and is routed to the four outputs.
The ′ALS157A and SN74AS157 present true
data. The ′ALS158 and SN74AS158 present
inverted data to minimize propagation delay time.
The SN54ALS157A and SN54ALS158 are
characterized for operation over the full military
temperature range of −55°C to 125°C. The
SN74ALS157A, SN74ALS158, SN74AS157, and
SN74AS158 are characterized for operation from
0°C to 70°C.
FUNCTION TABLE
INPUTS
OUTPUT Y
G
A/B
DATA
′
ALS157A
′
ALS158
G A/B
A
B
ALS157A
SN74AS157
ALS158
SN74AS158
H X X X L H
L LLXL H
L LHXH L
L HXLL H
L H X H H L
SN54ALS157A, SN54ALS158 ...J PACKAGE
SN74ALS157A, SN74ALS158,
SN74AS157, SN74AS158 ...D OR N PACKAGE
(TOP VIEW)
3212019
910111213
4
5
6
7
8
18
17
16
15
14
4A
4B
NC
4Y
3A
1B
1Y
NC
2A
2B
SN54ALS157A, SN54ALS158 . . . FK PACKAGE
(TOP VIEW)
1A A/B NC
3Y 3B G 2Y
GND
NC
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
A/B
1A
1B
1Y
2A
2B
2Y
GND
V
CC
G
4A
4B
4Y
3A
3B
3Y
NC − No internal connection
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