5-236

FAST AND LS TTL DATA

SN54/74LS139

FUNCTIONAL DESCRIPTION

The LS139 is a high speed dual 1-of-4 decoder/demultiplex-

er fabricated with the Schottky barrier diode process. The

device has two independent decoders, each of which accept

two binary weighted inputs (A0, A1) and provide four mutually

exclusive active LOW outputs (O0–O3). 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 LS139 generates all four minterms of two

variables. These four minterms are useful in some applica-

tions, replacing multiple gate functions as shown in Fig. a, and

thereby reducing the number of packages required in a logic

network.

TRUTH TABLE

INPUTS

OUTPUTS

E

A0

A1

O0

O1

O2

O3

H

X

X

H

H

H

H

L

L

L

L

H

H

H

L

H

L

H

L

H

H

L

L

H

H

H

L

H

L

H

H

H

H

H

L

H = HIGH Voltage Level

L = LOW Voltage Level

X = Don’t Care

GUARANTEED OPERATING RANGES

Symbol

Parameter

Min

Typ

Max

Unit

VCC

Supply Voltage

54

74

4.5

4.75

5.0

5.0

5.5

5.25

V

TA

Operating Ambient Temperature Range

54

74

– 55

0

25

25

125

70

°C

IOH

Output Current — High

54, 74

– 0.4

mA

IOL

Output Current — Low

54

74

4.0

8.0

mA

Figure a

E

A0

A1

E

A0

A1

E

A0

A1

E

A0

A1

O0

O1

O2

O3

E

A0

A1

E

A0

A1

E

A0

A1

E

A0

A1

O0

O1

O2

O3