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IC BLOCK DIAGRAMS AND TERMINAL DESCRIPTIONS -71
Q7172: TC74VHC138FT (3-8 Line Decoder)
BLOCK DIAGRAM
Select
Inputs
Enable
Inputs
ENABLE INPUTS
G1
G2A
X
H
X
X
L
X
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
PIN CONFIGURATION
1
A
2
B
3
C
4
G2A
5
G2B
6
G1
Logic Diagram
SELECT INPUTS
G2B
C
B
A
X
X
X
X
H
X
X
X
X
X
X
X
L
L
L
L
L
L
L
H
L
L
H
L
L
L
H
H
L
H
L
L
L
H
L
H
L
H
H
L
L
H
H
H
A
V
1
16
CC
B
Y0
2
15
C
Y1
3
14
G2A
4
13
Y2
G2B
5
12
Y3
6
11
G1
Y4
7
10
Y7
Y5
8
9
GND
Y6
OUTPUTS
Y0
Y1
Y2
Y3
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
TX-SR875
15
Y0
14
Y1
13
Y2
12
Y3
Data
Outputs
11
Y4
10
Y5
9
Y6
7
Y7
Y4
Y5
Y6
Y7
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
H
H
H
H
L
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