CD54AC138 Datasheet, PDF (2/7 Pages) Texas Instruments – 3-to-8-Line Decoders/Demultiplexers

CD54/74AC138, CD54/74ACT138, CD74AC238, CD74ACT238
Functional Diagram
1
A0
2
A1
3
A2
4
E1
5
E2
6
E3
AC/ACT AC/ACT
238 138
15
Y0
Y0
14
Y1
Y1
13
Y2
Y2
12
Y3
Y3
11
Y4
Y4
10
Y5
Y5
9
Y6
Y6
7
Y7
Y7
CD74AC/ACT138 TRUTH TABLE
INPUTS
ENABLE
ADDRESS
OUTPUTS
(NOTE 4)
E₃
E0
A₂
A₁
A₀
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
X
H
X
X
X
H
H
H
H
H
H
H
H
L
X
X
X
X
H
H
H
H
H
H
H
H
H
L
L
L
L
L
H
H
H
H
H
H
H
H
L
L
L
H
H
L
H
H
H
H
H
H
H
L
L
H
L
H
H
L
H
H
H
H
H
H
L
L
H
H
H
H
H
L
H
H
H
H
H
L
H
L
L
H
H
H
H
L
H
H
H
H
L
H
L
L
H
H
H
H
H
L
H
H
H
L
H
H
L
H
H
H
H
H
H
L
H
H
L
H
H
H
H
H
H
H
H
H
H
L
CD74AC/ACT238 TRUTH TABLE
INPUTS
ENABLE
ADDRESS
OUTPUTS
(NOTE 4)
E₃
E0
A₂
A₁
A₀
Y0
Y1
Y2
Y3
Y4
Y5
Y6
Y7
X
H
X
X
X
L
L
L
L
L
L
L
L
L
X
X
X
X
L
L
L
L
L
L
L
L
H
L
L
L
L
H
L
L
L
L
L
L
L
H
L
L
L
H
L
H
L
L
L
L
L
L
H
L
L
H
L
L
L
H
L
L
L
L
L
H
L
L
H
H
L
L
L
H
L
L
L
L
H
L
H
L
L
L
L
L
L
H
L
L
L
H
L
H
L
H
L
L
L
L
L
H
L
L
H
L
H
H
L
L
L
L
L
L
L
H
L
H
L
H
H
H
L
L
L
L
L
L
L
H
NOTES:
3. H = High Level, L = Low Level, X = Don’t Care
4. E0 = E1 + E2
2