HD74LS138

Rev.3.00, Jul.13.2005, page 2 of 7

Function Table

Inputs

Enable

Select

Outputs

G1

G2*

C

B

A

X

H

X

X

X

H

H

H

H

H

H

H

H

L

X

X

X

X

H

H

H

H

H

H

H

H

H

L

L

L

L

L

H

H

H

H

H

H

H

H

L

L

L

H

H

L

H

H

H

H

H

H

H

L

L

H

L

H

H

L

H

H

H

H

H

H

L

L

H

H

H

H

H

L

H

H

H

H

H

L

H

L

L

H

H

H

H

L

H

H

H

H

L

H

L

H

H

H

H

H

H

L

H

H

H

L

H

H

L

H

H

H

H

H

H

L

H

H

L

H

H

H

H

H

H

H

H

H

H

L

H ; high level, L ; low level, X ; irrelevant

Block Diagram

Select

Inputs

Enable

Inputs

A

B

C

Data

Outputs

Absolute Maximum Ratings

Item

Symbol

Ratings

Unit

Supply voltage

7

V

Input voltage

7

V

Power dissipation

400

mW

Storage temperature

Tstg

–65 to +150

°C

Note:

Voltage value, unless otherwise noted, are with respect to network ground terminal.

Recommended Operating Conditions

Item

Symbol

Min

Typ

Max

Unit

Supply voltage

4.75

5.00

5.25

V

—

—

–400

µA

Output current

—

—

8

mA

Operating temperature

Topr

–20

25

75

°C