Philips Semiconductors

Product specification

74ALS157/74ALS158

Data selector/multiplexer

74ALS157 Quad 2-input data selector/multiplexer, non-inverting

74ALS158 Quad 2-input data selector/multiplexer, inverting

2

1991 Feb 08

853–1129 01670

DESCRIPTION

The 74ALS157 is a quad 2-input multiplexer which selects 4 bits of

data from one of two sources under the control of a common select

input (S). The enable input (E) is active when Low. When E is High,

all of the outputs (Yn) are forced Low regardless of all other input

conditions.

Moving data from two registers to a common output bus is a typical

use of the 74ALS157. The state of the select input determines the

particular register from which data comes.

The device is the logic implementation of 4-pole, 2-position switch

where the position of the switch is determined by the logic levels

supplied to the select input. The 74ALS158 is similar but has

inverting outputs (Yn).

TYPE

TYPICAL

PROPAGATION DELAY

TYPICAL

SUPPLY CURRENT

(TOTAL)

74ALS157

6.0ns

6mA

74ALS158

6.0ns

6mA

ORDERING INFORMATION

ORDER CODE

DESCRIPTION

COMMERCIAL RANGE

DRAWING

NUMBER

16-pin plastic DIP

74ALS157N, 74ALS158N

SOT38-4

16-pin plastic SO

74ALS157D, 74ALS158D

SOT109-1

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74ALS (U.L.)

HIGH/LOW

LOAD VALUE

HIGH/LOW

Ina, Inb, Inc, Ind

Data inputs

1.0/1.0

20

µA/0.1mA

S

Select input

1.0/1.0

20

µA/0.1mA

E

Enable input

1.0/1.0

20

µA/0.1mA

Ya – Yd, Ya – Yd

Data outputs

20/240

0.4mA/24mA

NOTE:

One (1.0) ALS unit load is defined as: 20

µA in the High state and 0.1mA in the Low state.

PIN CONFIGURATION – 74ALS157

16

15

14

13

12

11

10

7

6

5

4

3

2

1

Yb

Yd

I0c

I1c

I1d

E

I0d

S

I0a

I1b

I1a

Ya

I0b

9

8

GND

Yc

SC00051

PIN CONFIGURATION – 74ALS158

16

15

14

13

12

11

10

7

6

5

4

3

2

1

Yb

Yd

I0c

I1c

I1d

E

I0d

S

I0a

I1b

I1a

Ya

I0b

9

8

GND

Yc

SC00052

LOGIC SYMBOL – 74ALS157

GND = Pin 8

SC00053

1

15

S

E

2356

11

10

14

I0a

I1a

I0b

I1b

I0c

I1c

I0d

Ya

Yb

Yc

Yd

479

12

13

I1d

LOGIC SYMBOL – 74ALS158

GND = Pin 8

SC00054

1

15

S

E

2356

11

10

14

I0a

I1a

I0b

I1b

I0c

I1c

I0d

Ya

Yb

Yc

Yd

479

12

13

I1d