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2

Logic Symbols

IEEE/IEC

Truth Table

H

= HIGH Voltage Level

L

= LOW Voltage Level

X

= Immaterial

Functional Description

The AC/ACT139 is a high-speed dual 1-of-4 decoder/

demultiplexer. The device has two independent decoders,

and provides four mutually exclusive active-LOW outputs

When E is HIGH all outputs are forced HIGH. The enable

can be used as the data input for a 4-output demultiplexer

application. Each half of the AC/ACT139 generates all four

minterms of two variables. These four minterms are useful

in some applications, replacing multiple gate functions as

shown in Figure 1, and thereby reducing the number of

packages required in a logic network.

FIGURE 1. Gate Functions (Each Half)

Logic Diagram

Please note that this diagram is provided only for the understanding of logic

operations and should not be used to estimate propagation delays.

Inputs

Outputs

E

H

X

X

HHHH

L

LLL

H

H

H

L

H

LH

LH

H

L

L

HHH

L

H

L

HHHHH

L