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FEATURES

 Integrated NV SRAM, Real-Time Clock,

Crystal, Power-Fail Control Circuit, and

Lithium Energy Source

 Standard JEDEC Bytewide 2k x 8 Static

RAM Pinout

 Clock Registers are Accessed Identically to

the Static RAM. These Registers are

Resident in the Eight Top RAM Locations

 Totally Nonvolatile with Over 10 Years of

Operation in the Absence of Power

 Access Times of 85ns and 100ns

 Quartz Accuracy ±1 Minute a Month at

+25°C, Factory Calibrated

 BCD-Coded Year, Month, Date, Day, Hours,

Minutes, and Seconds with Leap Year

Compensation Valid Up to 2100

 Power-Fail Write Protection Allows for

 Lithium Energy Source is Electrically

Disconnected to Retain Freshness Until

Power is Applied for the First Time

 UL Recognized

PIN CONFIGURATION

ORDERING INFORMATION

PART

VOLTAGE

RANGE

(V)

TEMP RANGE

PIN-PACKAGE TOP MARK

DS1642-85+

5.0

0°C to +70°C

24 EDIP (0.720a)

DS1642+85

DS1642-100+

5.0

0°C to +70°C

24 EDIP (0.720a)

DS1642+100

+Denotes a lead(Pb)-free/RoHS-compliant package.

A “+" indicates a lead(Pb)-free product. The top mark will include a “+” symbol on lead-free devices.

DS1642

Nonvolatile Timekeeping RAM

www.maxim-ic.com

A8

A9

WE

OE

A10

A7

A6

A5

A4

A3

A2

A1

A0

DQ0

DQ1

DQ2

GND

CE

DQ7

DQ6

DQ5

DQ4

DQ3

1

2

3

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

DS1642

ENCAPSULATED DIP

TOP VIEW

19-5266; Rev 5/10