DM74LS155 Fairchild Semiconductor, DM74LS155 Datasheet - Page 2

• Manufacturer Part Number: DM74LS155
• Description: Dual 2-Line to 4-Line Decoders/Demultiplexers
• Manufacturer: Fairchild Semiconductor

www.fairchildsemi.com
Function Tables
H
L
X
Note 1: C
Note 2: G
Logic Diagram
B
H
H
Select
X
X
L
L
LOW level
HIGH level
don’t care
C (Note 1)
A
X
H
H
X
L
L
X
H
H
H
H
L
L
L
L
inputs C1 and C2 connected together
inputs G1 and G2 connected together
Select
Inputs
Strobe
G1
H
L
L
L
L
X
B
H
H
H
H
X
Inputs
L
L
L
L
Data
C1
A
X
H
H
H
H
X
H
H
H
H
L
L
L
L
L
3-Line-to-8-Line Decoder or 1-Line-to-8-Line Demultiplexer
2-Line-to-4-Line Decoder or 1-Line-to-4-Line Demultiplexer
G (Note 2)
1Y0
Or Data
H
H
H
H
H
L
Strobe
H
L
L
L
L
L
L
L
L
1Y1
H
H
H
H
H
L
Outputs
1Y2
H
H
H
H
H
L
2Y0
(0)
H
H
H
H
H
H
H
H
L
1Y3
H
H
H
H
H
L
2Y1
(1)
H
H
H
H
H
H
H
H
L
2
Select
B
X
H
H
X
L
L
2Y2
(2)
H
H
H
H
H
H
H
H
L
A
H
H
X
L
L
X
Inputs
Strobe
2Y3
G2
(3)
H
X
H
H
H
H
H
H
H
H
L
L
L
L
L
Outputs
Data
1Y0
C2
(4)
H
H
H
H
H
H
H
H
X
H
L
L
L
L
L
2Y0
H
H
H
H
H
L
1Y1
(5)
H
H
H
H
H
H
H
H
L
2Y1
H
H
H
H
H
Outputs
L
1Y2
(6)
H
H
H
H
H
H
H
H
L
2Y2
H
H
H
H
H
L
1Y3
(7)
H
H
H
H
H
H
H
H
2Y3
L
H
H
H
H
H
L