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Hitachi Semiconductor |
HD74AC139/HD74ACT139
Dual 1-of-4 Decoder/Demultiplexer
Description
The HD74AC139/HD74ACT139 is a high-speed, dual 1-of-4 decoder/demultiplexer. The device has two
independent decoders, each accepting two inputs and providing four mutually-exclusive active-Low
outputs. Each decoder has an active-Low Enable input which can be used as a data input for a 4-output
demultiplexer. Each half of the HD74AC139/HD74ACT139 can be used as a function generator providing
all four minterms of two variables.
Features
• Multifunction Capability
• Two Completely Independent 1-of-4 Decoders
• Active Low Mutually Exclusive Outputs
• Outputs Source/Sink 24 mA
• HD74ACT139 has TTL-Compatible Inputs
HD74AC139/HD74ACT139
Pin Arrangement
Logic Symbol
Ea 1
A0a 2
A1a 3
O0a 4
O1a 5
O2a 6
O3a 7
GND 8
(Top view)
16 VCC
15 Eb
14 A0b
13 A1b
12 O0b
11 O1b
10 O2b
9 O3b
E A0 A1
DECODER a
O0 O1 O2 O3
Pin Names
A0, A1
E
O0 to O 3
Address Inputs
Enable Inputs
Outputs
E A0 A1
DECODER b
O0 O1 O2 O3
2
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