Functional Description

The ’AC/’ACT158 quad 2-input multiplexer selects four bits

of data from two sources under the control of a common Se-

lect input (S) and presents the data in inverted form at the

four outputs. The Enable input (E) is active-LOW. When E is

HIGH, all of the outputs (Z) are forced HIGH regardless of all

other inputs. The ’AC/’ACT158 is the logic implementation of

a 4-pole, 2-position switch where the position of the switch is

determined by the logic levels supplied to the Select input.

A common use of the ’AC/’ACT158 is the moving of data

from two groups of registers to four common output busses.

The particular register from which the data comes is deter-

mined by the state of the Select input. A less obvious use is

as a function generator. The ’AC/’ACT158 can generate four

functions of two variables with one variable common. This is

useful for implementing gating functions.

Truth Table

Inputs

Outputs

E

SI

0

I

1

Z

HX

X

X

H

LL

L

X

H

LL

H

X

L

LH

X

L

H

LH

X

H

L

H = HIGH Voltage Level

L = LOW Voltage Level

X = Immaterial

Logic Diagram

DS100273-5

Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.

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