Philips Semiconductors

Product specification

74ALS253

Dual 4-input multiplexer (3-State)

2

1991 Feb 08

853–1378 01670

FEATURES

DESCRIPTION

The 74ALS253 has two identical 4-input multiplexers with 3-State

outputs which select 2 bits from four sources by using common

select input (S0, S1). When the individual output enable (OEa,

OEb) inputs of the 4-input multiplexers are High, the outputs are

forced to a High impedance (Z) state.

The 74ALS253 is the logic implementation of 2-pole, 4-position

switch being determined by the logic levels supplied to the common

select inputs.

To avoid exceeding the maximum current ratings when the outputs

of the 3-State devices are tied together, all but one device must be

in the High impedance state. Therefore, only one output enable

must be achieved at a time.

TYPE

TYPICAL

PROPAGATION DELAY

TYPICAL

SUPPLY CURRENT

(TOTAL)

74ALS253

7.0ns

8mA

PIN CONFIGURATION

16

15

14

13

12

11

10

7

6

5

4

3

2

1

Ya

I2b

I1b

I0b

I3b

OEb

S0

OEa

S1

I0a

I3a

I2a

I1a

9

8

GND

Yb

SF00798

ORDERING INFORMATION

ORDER CODE

DESCRIPTION

COMMERCIAL RANGE

DRAWING

NUMBER

16-pin plastic DIP

74ALS253N

SOT38-4

16-pin plastic SO

74ALS253D

SOT109-1

16-pin plastic SSOP

Type II

74ALS253DB

SOT338-1

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74ALS (U.L.)

HIGH/LOW

LOAD VALUE

HIGH/LOW

I0a – I3a

Port A data inputs

1.0/1.0

20

µA/0.1mA

I0b – I3b

Port B data inputs

1.0/1.0

20

µA/0.1mA

S0, S1

Common select inputs

1.0/1.0

20

µA/0.1mA

OEa

Port A Output Enable input (active-Low)

1.0/1.0

20

µA/0.1mA

OEb

Port B Output Enable input (active-Low)

1.0/1.0

20

µA/0.1mA

Ya – Yb

3-State outputs

130/240

2.6mA/24mA

NOTE:

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

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

LOGIC SYMBOL

3

4

5

GND = Pin 8

SF00799

9

7

14

2

1

S0

S1

OEa

15

6

13

12

11

10

OEb

Ya

Yb

I0a

I1a

I2a

I3a

I0b

I1b

I2b

I3b

IEC/IEEE SYMBOL

SC00073

MUX

1

6

15

10

11

7

9

0

5

2

EN

4

3

13

12

1

3

0

G

0

3

2

14

2