TLF6395

June 1989

54LS155DM54LS155DM74LS155

54LS156DM54LS156DM74LS156

Dual 2-Line to 4-Line DecodersDemultiplexers

General Description

These TTL circuits feature dual 1-line-to-4-line demultiplex-

ers with individual strobes and common binary-address in-

puts in a single 16-pin package When both sections are

enabled by the strobes the common address inputs se-

quentially select and route associated input data to the ap-

propriate output of each section The individual strobes per-

mit activating or inhibiting each of the 4-bit sections as de-

sired Data applied to input C1 is inverted at its outputs and

data applied at C2 is true through its outputs The inverter

following the C1 data input permits use as a 3-to-8-line de-

coder or 1-to-8-line demultiplexer without external gating

Input clamping diodes are provided on these circuits to mini-

mize transmission-line effects and simplify system design

Features

Y

Applications

Dual 2-to-4-line decoder

Dual 1-to-4-line demultiplexer

3-to-8-line decoder

1-to-8-line demultiplexer

Y

Individual strobes simplify cascading for decoding or

demultiplexing larger words

Y

Input clamping diodes simplify system design

Y

Choice of outputs

Totem-pole (LS155)

Open-collector (LS156)

Y

Alternate MilitaryAerospace device (54LS155156) is

available Contact a National Semiconductor Sales Of-

ficeDistributor for specifications

Connection Diagram and Function Tables

Dual-In-Line Package

TLF6395 – 1

3-Line-to-8-Line Decoder or

1-Line-to-8-Line Demultiplexer

Inputs

Outputs

Select

Strobe

(0)

(1)

(2)

(3)

(4)

(5)

(6)

(7)

Or Data

C

BA

G

2Y0 2Y1 2Y2 2Y3 1Y0 1Y1 1Y2 1Y3

X X X

H

HHHHHHHH

L

L L

L

L

H

HHHHHH

L

L H

L

H

L

HHHHHH

L H L

L

HH

L

HHHHH

L H H

L

HHH

L

HHHH

H L L

L

HHHH

L

HHH

H L H

L

HHHHH

L

H

H

H H L

L

HHHHHH

L

H

H H H

L

HHHHHHH

L

Order Number 54LS155DMQB 54LS155FMQB

54LS155LMQB DM54LS155J DM54LS155W

DM74LS155M DM74LS155N 54LS156DMQB

54LS156FMQB DM54LS156J DM54LS156W

DM74LS156M or DM74LS156N

See NS Package Number E20A J16A

M16A N16E or W16A

2-Line-to-4-Line Decoder or

1-Line-to-4-Line Demultiplexer

Inputs

Outputs

Select

Strobe

Data

B

A

G1

C1

1Y0

1Y1

1Y2

1Y3

X

X

H

X

HHHH

L

L

L

H

L

HHH

L

H

L

H

HLH

H

H

L

L

H

H

HLH

H

H

L

H

HHH

L

X

X

X

L

HHHH

Inputs

Outputs

Select

Strobe

Data

B

A

G2

C2

2Y0

2Y1

2Y2

2Y3

X

X

H

X

HHHH

L

L

L

L

L

HHH

L

H

L

L

HLH

H

H

L

L

L

H

HLH

H

H

L

L

HHH

L

X

X

X

H

HHHH

C1995 National Semiconductor Corporation

RRD-B30M105Printed in U S A