Motorola MC74F157AN, MC54F157AJ Datasheet

4-67

FAST AND LS TTL DATA

QUAD 2-INPUT MULTIPLEXER

The MC74F157A is a high-speed quad 2-input multiplexer. Four bits of data
from two sources can be selected using the common Select and Enable in­puts. The four buffered outputs present the selected data in the true (non-in­verted) form. The F157A can also be used to generate any four of the 16 differ­ent functions to two variables.

• AC Enhanced Version of the F157

Z

c

CONNECTION DIAGRAM DIP (TOP VIEW)

1516 14 13 12 11 10

21 3 4 5 6 7

V

CC

9

8

E

I0cI

1cZcI0dI1dZd

S I

0aI1aZaI0bI1bZb

GND

LOGIC DIAGRAM

I

0aI1aI0bI1bI0c

I

1b

I

1cI0d

SEI

1d

Z

a

Z

b

Z

d

FUNCTION TABLE

Inputs Output

E S I

0

I

1

Z

H X X X L
L H X L L
L H X H H
L L L X L
L L H X H

H = HIGH Voltage Level; L = LOW Voltage Level; X = Don’t Care

MC74FXXXJ Ceramic
MC74FXXXN Plastic
MC74FXXXD SOIC

MC74F157A

QUAD 2-INPUT
MULTIPLEXER

FAST SHOTTKY TTL

J SUFFIX

CERAMIC

CASE 620-09

N SUFFIX

PLASTIC

CASE 648-08

16

1

16

1

ORDERING INFORMATION

16

1

D SUFFIX

SOIC

CASE 751B-03

LOGIC SYMBOL

12

13

14

15

1

2
3

4

7

5
6

11
10

9

Z

a

Z

b

Zc

Z

d

I

1a

I

0a

E

I

0c

I

1c

I

1d

I

0d

I

0b

I

1b

VCC = PIN 16
GND = PIN 8

S

4-68

FAST AND LS TTL DATA

MC74F157A

GUARANTEED OPERATING RANGES

Symbol Parameter Min Typ Max Unit

V

CC

Supply Voltage 74 4.5 5.0 5.5 V

T

A

Operating Ambient Temperature Range 74 0 25 70 °C

I

OH

Output Current — High 74 –1.0 mA

I

OL

Output Current — Low 74 20 mA

DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)

Limits

Symbol Parameter Min Typ Max Unit Test Conditions

V

IH

Input HIGH Voltage 2.0 V Guaranteed Input HIGH Voltage

V

IL

Input LOW Voltage 0.8 V Guaranteed Input LOW Voltage

V

IK

Input Clamp Diode Voltage –1.2 V IIN = –18 mA VCC = MIN

V

OH

Output HIGH Voltage 74 2.7 3.4 V

IOH = –1.0 mA

VCC = 4.75 V

74 2.5 VCC = 4.50 V

V

OL

Output LOW Voltage 0.35 0.5 V IOL = 20 mA VCC = MIN

I

IH

Input HIGH Current 20

µA VIN = 2.7 V VCC = MAX

100 µA VIN = 7.0 V

I

IL

Input LOW Current –0.6 mA VIN = 0.5 V VCC = MAX

I

OS

Output Short Circuit Current (Note 2) –60 –150 mA V

OUT

= 0 V VCC = MAX

I

CC

Power Supply Current 15 23 mA All Inputs = 4.5 V VCC = MAX

NOTES:

1. For conditions shown as MIN or MAX, use the appropriate value specified under guaranteed operating ranges.

2. Not more than one output should be shorted at a time, nor for more than 1 second.

AC CHARACTERISTICS

74F 74F

TA = +25°C

VCC = +5.0 V

CL = 50 pF

TA = 0°C to 70°C

VCC = 5.0 V ±10%

CL = 50 pF

Symbol Parameter Min Max Min Max

Unit

t

PLH

Propagation Delay 3.5 10 3.5 11

ns

t

PHL

S to Z

n

3.0 7.0 3.0 8.0

t

PLH

Propagation Delay 3.5 9.5 3.5 11

ns

t

PHL

E to Z

n

2.5 6.5 2.5 7.0

t

PLH

Propagation Delay 2.0 6.0 2.0 6.5

ns

t

PHL

In to Z

n

2.5 5.5 2.0 7.0

FUNCTIONAL DESCRIPTION

The F157A is a quad 2-input multiplexer. It selects four bits

of data from two sources under the control of a common Select
input (S). The Enable input (E

) is active LOW. When E is
HIGH, all of the outputs (Z) are forced LOW regardless of all
other inputs. The F157A 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. The
logic equations for the outputs are shown below:

Za = E

• (I1a • S + I0a • S)

Zc = E

• (I1c • S + I0c • S)

A common use of the F157A is the moving of data from two
groups of registers to four common output busses. The partic­ular register from which the data comes is determined by the
state of the Select input. A less obvious use is as a function
generator. The F157A can generate any four of the 16 dif ferent
functions of two variables with one variable common. This is
useful for implementing highly irregular logic.

Zb = E

• (I1b • S + I0b • S)

Zd = E

• (I1d • S + I0d • S)