DS1643/DS1643P

2 of 17

PIN DESCRIPTION

PIN

PDIP

PowerCap

NAME

FUNCTION

1

1, 2, 3,

31–34

N.C.

No Connection

2

30

A12

3

25

A7

4

24

A6

5

23

A5

6

22

A4

7

21

A3

8

20

A2

9

19

A1

10

18

A0

21

28

A10

23

29

A11

24

27

A9

25

26

A8

Address Inputs

11

16

DQ0

12

15

DQ1

13

14

DQ2

15

13

DQ3

16

12

DQ4

17

11

DQ5

18

10

DQ6

19

9

DQ7

Data Input/Output

20

8

CE

Active-Low Chip-Enable Input

22

7

OE

Active-Low Output-Enable Input

26

—

CE2

Chip-Enable 2 Input (Active High)

27

6

WE

Active-Low Write-Enable Input

28

5

Power-Supply Input

—

4

PFO

Active-Low Power-Fail Output. This open-drain pin requires a

pullup resistor for proper operation.

14

17

GND

Ground

—

X1, X2,

Crystal Connection, Battery Connection