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GENERAL DESCRIPTION

The DS1553 is a full-function, year-2000-

compliant (Y2KC) real-time clock/calendar (RTC)

with an RTC alarm, watchdog timer, power-on

reset, battery monitor, and 8k x 8 nonvolatile static

RAM. User access to all registers within the

DS1553 is accomplished with a byte-wide

interface as shown in Figure 1. The RTC registers

contain century, year, month, date, day, hours,

minutes, and seconds data in 24-hour BCD format.

Corrections for day of month and leap year are

made automatically.

Pin Configurations appear at end of data sheet.

FEATURES



Integrated NV SRAM, RTC, Crystal, Power-Fail

Control Circuit, and Lithium Energy Source



Clock Registers are Accessed Identically to the

Static RAM; These Registers are Resident in the

16 Top RAM Locations



Totally Nonvolatile with Over 10 Years of

Operation in the Absence of Power



Precision Power-On Reset



Programmable Watchdog Timer and RTC Alarm



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

Minutes, and Seconds with Automatic Leap Year

Compensation Valid Up to the Year 2100



Battery Voltage Level Indicator Flag



Power-Fail Write Protection Allows for

10%

Disconnected to Retain Freshness Until Power is

Applied for the First Time

ORDERING INFORMATION

PART

VOLTAGE (V)

TEMP RANGE

PIN-PACKAGE

TOP MARK**

DS1553-85+

5.0

0°C to +70°C

28 EDIP (0.740)

DS1553+85

DS1553-100+

5.0

0°C to +70°C

28 EDIP (0.740)

DS1553+100

DS1553W-120+

3.3

0°C to +70°C

28 EDIP (0.740)

DS1553W+120

DS1553W-150+

3.3

0°C to +70°C

28 EDIP (0.740)

DS1553W+150

DS1553P-85+

5.0

0°C to +70°C

34 PowerCap*

DS1553P+85

DS1553P-100+

5.0

0°C to +70°C

34 PowerCap*

DS1553P+100

DS1553WP-120+

3.3

0°C to +70°C

34 PowerCap*

DS1553WP+120

DS1553WP-150+

3.3

0°C to +70°C

34 PowerCap*

DS1553WP+150

DS9034PCX+

3

0°C to +70°C

—

DS9034PCX

**A “+” symbol anywhere on the top mark indicates a lead(Pb)-free package.

DS1553

64kB, Nonvolatile, Year-2000-Compliant

Timekeeping RAM

www.maxim-ic.com

19-5480; Rev 8/10