ꢀꢁꢂ ꢃꢄ ꢀꢅ ꢆꢅ ꢄ
ꢆ ꢇꢈ ꢉꢁꢊ ꢋꢌꢍ ꢋꢎ ꢇꢈ ꢉꢁ ꢊꢋꢏꢊ ꢐꢍ ꢏꢊꢑꢒ ꢏꢊꢓ ꢔꢈꢌꢉ ꢕ ꢈꢊ ꢖꢊ ꢑ
ꢗ ꢉꢌ ꢘꢋꢄꢏꢏ ꢑꢊꢀꢀ ꢋꢑꢊ ꢙ ꢉ ꢀꢌ ꢊꢑ ꢀ
SDAS060C − APRIL 1982 − REVISED DECEMBER 1994
D OR N PACKAGE
(TOP VIEW)
• Combines Decoder and 3-Bit Address
Register
• Incorporates Two Enable Inputs to Simplify
A
B
V
CC
1
2
3
4
5
6
7
8
16
15
14
13
12
Cascading
Y0
Y1
Y2
Y3
• Package Options Include Plastic
Small-Outline (D) Packages and Standard
Plastic (N) 300-mil DIPs
C
CLK
G2
G1
Y7
11 Y4
description
10
9
Y5
Y6
The SN74AS131A is
a
3-line to 8-line
GND
decoder/demultiplexer with registers on the three
address inputs. When the clock (CLK) input goes
from low to high, the device acts as a decoder/
demultiplexer and the address present at the select (A, B, and C) inputs is stored in the registers. Further
address changes are ignored until the next rising transition of CLK. The output-enable (G1, G2) inputs control
the state of the outputs independently of the select or CLK inputs. All of the outputs are high unless G1 is high
and G2 is low. This device is ideally suited for implementing glitch-free decoders in strobed (stored-address)
applications in bus-oriented systems.
The SN74AS131A is characterized for operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
OUTPUTS
ENABLE
G1 G2
SELECT
CLK
C
X
X
L
B
X
X
L
A
X
X
L
Y0
H
H
L
Y1
H
H
H
L
Y2
H
H
H
H
L
Y3
H
H
H
H
H
L
Y4
H
H
H
H
H
H
L
Y5
H
H
H
H
H
H
H
L
Y6
H
H
H
H
H
H
H
H
L
Y7
H
H
H
H
H
H
H
H
H
L
X
X
L
H
X
L
L
L
L
L
L
L
L
L
X
↑
H
H
H
H
H
H
H
H
H
↑
L
L
H
L
H
H
H
H
H
H
H
↑
L
H
H
L
H
H
H
H
H
H
↑
L
H
L
H
H
H
H
H
↑
H
H
H
H
X
H
H
H
H
↑
↑
L
H
L
H
H
H
H
H
X
H
H
↑
H
X
H
L or H
Outputs corresponding to stored address = L; all others = H.
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Copyright 1994, Texas Instruments Incorporated
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ꢡ ꢥ ꢢ ꢡꢚ ꢛꢯ ꢝꢜ ꢠ ꢨꢨ ꢦꢠ ꢞ ꢠ ꢟ ꢥ ꢡ ꢥ ꢞ ꢢ ꢪ
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1
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