SN74ALS870

DUAL 16-BY-4 REGISTER FILES

SDAS139A – DECEMBER 1982 – REVISED JANUARY 1995

3

POST OFFICE BOX 655303

logic diagram (positive logic)

REG1

REG2

Decoder

BIN/Y

16

1

2

3

4

15

0

Decoder

BIN/Y

16

1

2

3

4

15

0

16

16

Three Identical Channels Not Shown

2A0

2A1

2A2

2A3

DQB1

1A0

1A1

1A2

1A3

S0

S1

S2

S3

1W

2W

DQA1

RAM 16

×1

A

A,D

15

0

A

A

A,D

15

0

A

RAM 16

×1

2

3

4

5

1

23

7

17

6

18

8

19

20

21

22

13

7 V

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

7 V

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

I/O ports

5.5 V

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

Voltage applied to a disabled 3-state output

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.