5-253

FAST AND LS TTL DATA

SN54/74LS151

LOGIC DIAGRAM

S2

S1

S0

E

I0

I1

I2

I3

I4

I5

I6

I7

Z Z

14

1

2

6

7

3

4

5

9

11

12

10

13

15

VCC = PIN 16

GND = PIN 8

= PIN NUMBERS

FUNCTIONAL DESCRIPTION

The LS151 is a logical implementation of a single pole,

8-position switch with the switch position controlled by the

state of three Select inputs, S0, S1, S2. Both assertion and

negation outputs are provided. The Enable input (E) is active

LOW. When it is not activated, the negation output is HIGH

and the assertion output is LOW regardless of all other inputs.

The logic function provided at the output is:

Z = E

⋅ (I0 ⋅ S0 ⋅ S1 ⋅ S2 + ⋅ I1 ⋅ S0 ⋅ S1 ⋅ S2 + I2 ⋅ S0 ⋅ S1 ⋅ S2

+ I3 ⋅ S0 ⋅ S1 ⋅ S2 + I4 ⋅ S0 ⋅ S1 ⋅ S2 + I5 ⋅ S0 ⋅ S1 ⋅ S2 + I6 ⋅ S0

⋅ S1 ⋅ S2 + I7 ⋅ S0 ⋅ S1 ⋅ S2).

The LS151 provides the ability, in one package, to select

from eight sources of data or control information. By proper

manipulation of the inputs, the LS151 can provide any logic

function of four variables and its negation.

TRUTH TABLE

E

S2 S1 S0 I0

I1

I2

I3

I4

I5

I6

I7

Z

Z

H

X

X

X

X

X

X

X

X

X

X

X

H

L

L

L

L

L

L

X

X

X

X

X

X

X

H

L

L

L

L

L

H

X

X

X

X

X

X

X

L

H

L

L

L

H

X

L

X

X

X

X

X

X

H

L

L

L

L

H

X

H

X

X

X

X

X

X

L

H

L

L

H

L

X

X

L

X

X

X

X

X

H

L

L

L

H

L

X

X

H

X

X

X

X

X

L

H

L

L

H

H

X

X

X

L

X

X

X

X

H

L

L

L

H

H

X

X

X

H

X

X

X

X

L

H

L

H

L

L

X

X

X

X

L

X

X

X

H

L

L

H

L

L

X

X

X

X

H

X

X

X

L

H

L

H

L

H

X

X

X

X

X

L

X

X

H

L

L

H

L

H

X

X

X

X

X

H

X

X

L

H

L

H

H

L

X

X

X

X

X

X

L

X

H

L

L

H

H

L

X

X

X

X

X

X

H

X

L

H

L

H

H

H

X

X

X

X

X

X

X

L

H

L

L

H

H

H

X

X

X

X

X

X

X

H

L

H

H = HIGH Voltage Level

L = LOW Voltage Level

X = Don’t Care