Philips Semiconductors

Product specification

74ALS244A/74ALS244A-1

Octal buffer (3-State)

2

1991 Feb 08

853–1277 01670

FEATURES

DESCRIPTION

The 74ALS244A is an octal buffer that is ideal for driving bus lines or

buffer memory address registers. The outputs are all capable of

sinking 24mA and sourcing up to 15mA, producing very good

capacitive drive characteristics. The device features two output

enables, OEa and OEb, each controlling four of the 3-State outputs.

5.0V

±0.25V.

TYPE

TYPICAL

PROPAGATION

DELAY

TYPICAL

SUPPLY CURRENT

(TOTAL)

74ALS244A

4.5ns

17mA

74ALS244A-1

4.5ns

17mA

PIN CONFIGURATION

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20 VCC

OEa

Ia0

Yb0

Ia1

Yb1

Ia2

Yb2

Ia3

Yb3

GND

SF00227

OEb

Ya0

Ib0

Ya1

Ib1

Ya2

Ib2

Ya3

Ib3

ORDERING INFORMATION

ORDER CODE

DESCRIPTION

COMMERCIAL RANGE

DRAWING

NUMBER

20-pin plastic DIP

74ALS244AN,

74ALS244A-1N

SOT146-1

20-pin plastic SOL

74ALS244AD,

744ALS244A-1D

SOT163-1

20-pin plastic

SSOP Type II

74ALS244ADB,

74ALS244A-1DB

SOT339-1

INPUT AND OUTPUT LOADING AND FAN-OUT TABLE

PINS

DESCRIPTION

74ALS (U.L.)

HIGH/LOW

LOAD VALUE

HIGH/LOW

Ian, Ibn

Data inputs

1.0/1.0

20

µA/0.1mA

OEa, OEb

Output Enable inputs (active-Low)

1.0/1.0

20

µA/0.1mA

Yan, Ybn

Data outputs

750/240

15mA/24mA

Yan, Ybn

Data outputs (-1 version)

750/480

15mA/48mA

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

OEa

1

SF00228

2

4

6

8

17

15

13

11

18

16

14

12

3

5

7

9

Ia0

Ia1

Ia2

Ia3

Ib0

Ib1

Ib2

Ib3

Ya0

Ya1 Ya2

Ya3 Yb0 Yb1 Yb2 Yb3

VCC = Pin 20

GND = Pin 10

OEb

19

IEC/IEEE SYMBOL

1

2D

EN1

EN2

1

2

19

2

4

6

8

17

15

13

11

18

16

14

12

3

5

7

9

SF00229