DESCRIPTION

The DS1251 4096K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 512K words by 8 bits) with a built-in real-time clock. The DS1251Y has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock.

FEATURES

■ Real-Time Clock Keeps Track of Hundredths Of Seconds, Minutes, Hours, Days, Date of the Month, Months, and Years

■ 512K x 8 NV SRAM Directly Replaces Volatile Static RAM or EEPROM

■ Embedded Lithium Energy Cell Maintains Calendar Operation and Retains RAM Data

■ Watch Function is Transparent to RAM Operation

■ Automatic Leap Year Compensation Valid Up to 2100

■ Over 10 Years of Data Retention in the Absence of Power

■ Full 10 Operating Range

■ Lithium Energy Source is Electrically Disconnected to Retain Freshness Until Power is Applied for the First Time

■ DIP Module Only

??? – Standard 32-Pin JEDEC Pinout

??? – Upward Compatible with the DS1248

■ PowerCap Module Board Only

??? ? Surface Mountable Package for Direct Connection to PowerCap Containing Battery and Crystal

??? ? Replaceable Battery (PowerCap)

??? ? Pin-for-Pin Compatible with Other Densities of DS124xP Phantom Clocks

■ Underwriters Laboratories (UL) Recognized (www.maxim-ic.com/qa/info/ul/)