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2

Unit Loading/Fan Out

Truth Table

H

= HIGH Voltage Level

L

= LOW

X

= Immaterial

Functional Description

The F153 is a dual 4-input multiplexer. It can select two bits

of data from up to four sources under the control of the

can be used to strobe the outputs independently. When the

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 as

follows:

The F153 can be used to move data from a group of regis-

ters 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 as a func-

tion generator. The F153 can generate two functions of

three variables. This is useful for implementing highly irreg-

ular random logic.

Logic Diagram

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

Pin Names

Description

U.L.

HIGH/LOW

Side A Data Inputs

1.0/1.0

20

µA/−0.6 mA

Side B Data Inputs

1.0/1.0

20

µA/−0.6 mA

Common Select Inputs

1.0/1.0

20

µA/−0.6 mA

Side A Enable Input (Active LOW)

1.0/1.0

20

µA/−0.6 mA

Side B Enable Input (Active LOW)

1.0/1.0

20

µA/−0.6 mA

Side A Output

50/33.3

−1 mA/20 mA

Side B Output

50/33.3

−1 mA/20 mA

Select Inputs

Inputs (a or b)

Output

E

Z

X

X

H

XXXX

L

L

L

L

L

XXX

L

L

L

L

H

XXX

H

H

L

LX

LX

X

L

HL

L

X

H

X

X

H

LH

L

X

X

L

X

L

LH

L

X

X

H

X

H

H

H

L

XXX

L

L

H

H

L

XXX

H

H