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Rainbow Electronics DS1251Y User Manual

Features, Pin assignment

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FEATURES

§ Real-time clock keeps track of hundredths of

seconds, minutes, hours, days, date of the
month, months, and years

§ 512k x 8 NV SRAM directly replaces

volatile static RAM or EEPROM

§ Embedded lithium energy cell maintains

calendar operation and retains RAM data

§ Watch function is transparent to RAM

operation

§ Month and year determine the number of

days in each month; valid up to 2100

§ Over 10 years of data retention in the

absence of power

§ Full 10% operating range

§ Lithium energy source is electrically

disconnected to retain freshness until power
is applied for the first time

§ DIP Module only

– Standard 32-pin JEDEC pinout
– Upward comparable with the DS1248

§ PowerCap

®

Module Board only

– Surface mountable package for direct

connection to PowerCap containing
battery and crystal

– Replaceable battery (PowerCap)
– Pin for pin compatible with other densities

of DS124XP phantom clocks

PIN ASSIGNMENT

DS1251/DS1251P

4096k NV SRAM with Phantom Clock

www.maxim-ic.com

13

1
2
3
4
5
6
7
8
9
10
11
12

14

31

32-Pin Encapsulated Package

740mil Flush

A14

A7

A5
A4
A3
A2
A1
A0

DQ1

DQ0

V

CC

A15
A17
WE
A13
A8
A9
A11
OE
A10
CE
DQ7

DQ5

DQ6

32

30
29
28
27
26
25
24
23
22
21

19

20

A16

A12

A6

A18/RST

DQ2

GND

15
16

18
17

DQ4
DQ3

1

RST

2

3

A15

A16

NC

V

CC

WE

OE

CE

DQ7

DQ6

DQ5

DQ4

DQ3

DQ2

DQ1

DQ0

GND

4

5

6

7

8

9

10

11

12

13

14

15

16

17

A17

A14

33

32

31

30

29

28

27

26

25

24

23

22

21

20

19

18

A13

A12

A11

A10

A9

A8

A7

A6

A5

A4

A3

A2

A1

A0

34

A18

X1 GND V

BAT

X2

34-Pin PowerCap Module Board

(Uses DS9034PCX PowerCap)

PowerCap is a registered trademark of Dallas Semiconductor.