MOTOROLA SN74LS42DR2, SN74LS42M, SN74LS42MEL, SN74LS42ML1, SN74LS42ML2 Datasheet

 Semiconductor Components Industries, LLC, 1999

December, 1999 – Rev. 6

1 Publication Order Number:

SN74LS42/D

SN74LS42

One-of-Ten Decoder

The LSTTL /MSI SN74LS42 is a Multipurpose Decoder designed
to accept four BCD inputs and provide ten mutually exclusive outputs.
The LS42 is fabricated with the Schottky barrier diode process for
high speed and is completely compatible with all ON Semiconductor
TTL families.

• Multifunction Capability

• Mutually Exclusive Outputs

• Demultiplexing Capability

• Input Clamp Diodes Limit High Speed Termination Effects

GUARANTEED OPERATING RANGES

Symbol Parameter Min Typ Max Unit

V

CC

Supply Voltage 4.75 5.0 5.25 V

T

A

Operating Ambient

T emperature Range

0 25 70 °C

I

OH

Output Current – High –0.4 mA

I

OL

Output Current – Low 8.0 mA

LOW

POWER

SCHOTTKY

Device Package Shipping

ORDERING INFORMATION

SN74LS42N 16 Pin DIP 2000 Units/Box
SN74LS42D 16 Pin

SOIC

D SUFFIX

CASE 751B

http://onsemi.com

2500/Tape & Reel

PLASTIC
N SUFFIX
CASE 648

16

1

16

1

SN74LS42

http://onsemi.com

2

LOGIC DIAGRAM

1 2 3 4 5 60

A

0

A

1

A

2

A

3

987

VCC = PIN 16
GND = PIN 8

= PIN NUMBERS

LOGIC SYMBOL

VCC = PIN 16
GND = PIN 8

15 14 13 12

0123456789

123456791011

A

0A1A2A3

14 13 12 11 10 9

123456

V

CC

7

16 15

8

A

0A1A2A3

9 8 7

0 1 2 3 4 5 6 GND

CONNECTION DIAGRAM DIP (TOP VIEW)

NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram)
as the Dual In-Line
Package.

Address Inputs
Outputs, Active LOW

A

0

– A

3

0 to 9

0.5 U.L.
10 U.L.

0.25 U.L.
5 U.L.

NOTES:

a) 1 TTL Unit Load (U.L.) = 40 mA HIGH/1.6 mA LOW.

HIGH LOW

(Note a)LOADING

PIN NAMES

15 14 13 12

12 3456791011

SN74LS42

http://onsemi.com

3

FUNCTIONAL DESCRIPTION

The LS42 decoder accepts four active HIGH BCD inputs
and provides ten mutually exclusive active LOW outputs, as
shown by logic symbol or diagram. The active LOW outputs
facilitate addressing other MSI units with LOW input
enables.

The logic design of the LS42 ensures that all outputs
are HIGH when binary codes greater than nine are applied
to the inputs.

The most significant input A

3

produces a useful inhibit
function when the LS42 is used as a one-of-eight decoder.
The A3 input can also be used as the Data input in an 8-output
demultiplexer application.

TRUTH TABLE

A0A1A2A30 1 2 3 4 5 6 7 8 9

L
H
L
H
L
H
L
H
L
H
L
H
L
H
L
H

L
L
H
H
L
L
H
H
L
L
H
H
L
L
H
H

L
L
L
L
H
H
H
H
L
L
L
L
H
H
H
H

L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H

L
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H

H
L
H
H
H
H
H
H
H
H
H
H
H
H
H
H

H
H

L
H
H
H
H
H
H
H
H
H
H
H
H
H

H
H
H

L
H
H
H
H
H
H
H
H
H
H
H
H

H
H
H
H
L
H
H
H
H
H
H
H
H
H
H
H

H
H
H
H
H
L
H
H
H
H
H
H
H
H
H
H

H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
H

H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H

H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H

H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H

H = HIGH Voltage Level
L = LOW Voltage Level