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2

Unit Loading/Fan Out

Functional Description

The F139 is a high-speed dual 1-of-4 decoder/demulti-

plexer. The device has two independent decoders, each of

Each decoder has 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 F139 generates all four minterms of two

variables. These four minterms are useful in some applica-

tions, 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.

Pin Names

Description

U.L.

Address Inputs

1.0/1.0

20

µA/−0.6 mA

E

Enable Inputs (Active LOW)

1.0/1.0

20

µA/−0.6 mA

Outputs (Active LOW)

50/33.3

−1 mA/20 mA