SN74ALS638A, SN74ALS639A, SN74AS638A, SN74AS639

OCTAL BUS TRANSCEIVERS

SDAS123A – DECEMBER 1983 – REVISED JANUARY 1995

2

POST OFFICE BOX 655303

B2

17

B3

16

B4

15

A5

6

A6

7

A7

8

A8

9

A2

3

A3

4

A4

5

OE

A1

2

G3

19

3 EN2 [AB]

B5

14

B6

13

B7

12

B8

11

B1

18

3 EN1 [BA]

1

DIR

1

2

B2

17

B3

16

B4

15

A5

6

A6

7

A7

8

A8

9

A2

3

A3

4

A4

5

OE

A1

2

G3

19

3 EN2 [AB]

B5

14

B6

13

B7

12

B8

11

B1

18

3 EN1 [BA]

1

DIR

1

2

SN74ALS638A, SN74AS638A

SN74ALS639A, SN74AS639

† These symbols are in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.

logic diagrams (positive logic)

SN74ALS638A, SN74AS638A

SN74ALS639A, SN74AS639

To Seven Other Transceivers

OE

A1

DIR

B1

19

2

1

18

To Seven Other Transceivers

OE

A1

DIR

B1

19

2

1

18

7 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A-bus I/O ports

7 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

B-bus I/O ports

5.5 V

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

0

°C to 70°C

. . . . . . . . . . . . . . . . .

Storage temperature range

– 65

°C to 150°C

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

‡ Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and

functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not

implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.