SN74LS153

3

LOGIC DIAGRAM

VCC = PIN 16

GND = PIN 8

= PIN NUMBERS

Ea I0a

I1a

I2a

I3a

S1

S0

I0b

I1b

I2b

I3b Eb

Za

Zb

14

12

6

7

3

4

5

9

11

12

10

13

15

FUNCTIONAL DESCRIPTION

The LS153 is a Dual 4-input Multiplexer fabricated with

Low Power, Schottky barrier diode process for high speed.

It can select two bits of data from up to four sources under

the control of the common Select Inputs (S0, S1). The two

4-input multiplexer circuits have individual active LOW

Enables (Ea, Eb) which can be used to strobe the outputs

independently. When the Enables (Ea, Eb) are HIGH, the

corresponding outputs (Za, Zb) are forced LOW.

The LS153 is the logic implementation of a 2-pole,

4-position switch, where the position of the switch is

determined by the logic levels supplied to the two Select

Inputs. The logic equations for the outputs are shown below.

Za = Ea ⋅ (I0a ⋅ S1 ⋅ S0 + I1a ⋅ S1 ⋅ S0 + I2a ⋅ S1 ⋅ S0 +

I3a ⋅ S1 ⋅ S0)

Zb = Eb ⋅ (I0b ⋅ S1 ⋅ S0 + I1b ⋅ S1 ⋅ S0 + I2b ⋅ S1 ⋅ S0 +

I3b ⋅ S1 ⋅ S0)

The LS153 can be used to move data from a group of

registers to a common output bus. The particular register

from which the data came would be determined by the state

of the Select Inputs. A less obvious application is a function

generator. The LS153 can generate two functions of three

variables. This is useful for implementing highly irregular

random logic.

TRUTH TABLE

SELECT INPUTS

INPUTS (a or b)

OUTPUT

S0

S1

E

I0

I1

I2

I3

Z

X

X

H

X

X

X

X

L

L

LL

L

XXX

L

L

LL

H

XXX

H

H

LL

X

LX

X

L

H

LL

X

HX

X

H

L

HL

X

XLX

L

L

HL

X

XHX

H

H

HL

X

XX

L

L

H

H

L

X

X

X

H

H

H = HIGH Voltage Level

L = LOW Voltage Level

X = Don’t Care

www.sycelectronica.com.ar