DS1553

· 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% V_CC Power-Supply Tolerance
· Lithium Energy Source is Electrically Disconnected to Retain Freshness Until Power is Applied for the First Time

Voltage Range on Any Pin Relative to Ground ....................................................-0.3V to +6.0V
Storage Temperature Range ..............................................................................-40 to +85
Soldering Temperature .......................................260 for 10 seconds (DIP Package) (Note 8)
                                       .............................................See IPC/JEDEC Standard J-STD-020A for
                                       .........................................................................Surface Mount Devices

This is a stress rating only and functional operation of  the device at these or any other  conditions above those indicated  in the operation sections of this specification is not implied. Exposure to absolute maximum rating onditions for extended periods of time may affect reliability.

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 bytewide 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.