MC74AC139, MC74ACT139

http://onsemi.com

2

DECODER a

Figure 2. Logic Symbol

DECODER b

NOTE: This diagram is provided only for the understanding of logic

operations and should not be used to estimate propagation

delays.

Figure 3. Logic Diagram

FUNCTIONAL DESCRIPTION

The MC74AC139/74ACT139 is a high−speed dual

1−of−4 decoder/demultiplexer. The device has two

independent decoders, each of which accepts two binary

an active−LOW enable (E). 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

MC74AC139/74ACT139 generates all four minterms of

two variables. These four minterms are useful in some

applications, replacing multiple gate functions as shown in

Figure 4, and thereby reducing the number of packages

required in a logic network.

E

E

E

E

E

E

E

E

Figure 4. Gate Functions (Each Half)