1 of 11

091404

FEATURES

§ Converts CMOS SRAM into nonvolatile

memory

§ Unconditionally write-protects SRAM when

§ Automatically switches to battery backup

§ Monitors voltage of a lithium cell and

provides advanced warning of impending

battery failure

§ Signals low-battery condition on active low

Battery Warning output signal

§ Optional 5% or 10% power-fail detection

§ Space-saving 8-pin DIP and SOIC packages

§ Optional 16-pin SOIC and 20-pin TSSOP

versions reset processor when power failure

occurs and hold processor in reset during

system power-up

§ Industrial temperature range of -40°C to

+85°C

PIN ASSIGNMENT

PIN DESCRIPTION

- +5V Power Supply Input

- SRAM Power Supply Output

- Backup Battery Input

CEI

- Chip Enable Input

CEO

- Chip Enable Output

TOL

BW

- Battery Warning Output

(Open Drain)

RST

- Reset Output (Open Drain)

GND

- Ground

NC

- No Connection

DESCRIPTION

The DS1312 Nonvolatile Controller with Battery Monitor is a CMOS circuit which solves the application

problem of converting CMOS RAM into nonvolatile memory. Incoming power is monitored for an out-

of-tolerance condition. When such a condition is detected, chip enable is inhibited to accomplish write

protection and the battery is switched on to supply the RAM with uninterrupted power. Special circuitry

uses a low-leakage CMOS process which affords precise voltage detection at extremely low battery

consumption.

DS1312

Nonvolatile Controller with Lithium

Battery Monitor

www.dalsemi.com

1

2

3

4

20

19

18

17

5

6

7

8

9

10

11

12

13

14

15

16

NC

RST

NC

NC

BW

NC

CEO

NC

CEI

NC

NC

NC

NC

TOL

NC

NC

GND

DS1312E 20-Pin TSSOP

1

2

3

4

8

7

6

5

GND

TOL

BW

CEO

CEI

DS1312S-2 8-Pin SOIC

(150-mil)

1

2

3

4

8

7

6

5

GND

TOL

BW

CEO

CEI

DS1312 8-Pin DIP

(300-mil)

1

2

3

4

16

15

14

13

5

6

7

89

10

11

12

NC

NC

NC

TOL

NC

GND

NC

RST

NC

BW

CEO

NC

CEI

DS1312S 16-Pin SOIC

(300-mil)