1 of 10

111899

FEATURES

10 years minimum data retention in the

absence of external power

Data is automatically protected during power

loss

Directly replaces 8k x 8 volatile static RAM

or EEPROM

Unlimited write cycles

Low-power CMOS

JEDEC standard 28-pin DIP package

Read and write access times as fast as 70 ns

Lithium energy source is electrically

disconnected to retain freshness until power

is applied for the first time

(DS1225AB)

Optional industrial temperature range of

-40°C to +85°C, designated IND

PIN ASSIGNMENT

28-Pin ENCAPSULATED PACKAGE

720-mil EXTENDED

PIN DESCRIPTION

A0-A12

- Address Inputs

DQ0-DQ7

- Data In/Data Out

CE

- Chip Enable

WE

- Write Enable

OE

- Output Enable

- Power (+5V)

GND

- Ground

NC

- No Connect

DESCRIPTION

The DS1225AB and DS1225AD are 65,536-bit, fully static, nonvolatile SRAMs organized as 8192 words

by 8 bits. Each NV SRAM has a self-contained lithium energy source and control circuitry which

energy source is automatically switched on and write protection is unconditionally enabled to prevent

data corruption. The NV SRAMs can be used in place of existing 8k x 8 SRAMs directly conforming to

the popular bytewide 28-pin DIP standard. The devices also match the pinout of the 2764 EPROM and

the 2864 EEPROM, allowing direct substitution while enhancing performance. There is no limit on the

number of write cycles that can be executed and no additional support circuitry is required for

microprocessor interfacing.

DS1225AB/AD

64k Nonvolatile SRAM

www.dalsemi.com

15

13

27

A7

A5

A3

A2

A1

A0

DQ0

DQ1

GND

DQ2

VCC

WE

NC

A8

A9

A11

OE

A10

CE

DQ7

DQ6

DQ5

DQ3

DQ4

1

2

3

4

5

6

7

8

9

10

11

12

14

28

26

25

24

23

22

21

20

19

18

17

16

A12

A6

A4

NC