GENERAL DESCRIPTION

The DS1254 is a fully nonvolatile static RAM (NV SRAM) (organized as 2M words by 8 bits) with built-in real-time clock. It has a self-contained lithium energy source and control circuitry that constantly monitors VCC for an out-oftolerance condition. When such a condition occurs, the DS1254 makes use of an attached DS3800 battery cap to maintain clock information and preserve stored data while protecting that data by disallowing all memory accesses. Additionally, the DS1254 has dedicated circuitry for monitoring the status of an attached DS3800 battery cap.

FEATURES

■ Real-Time Clock (RTC) Keeps Track of Hundredths of

   Seconds, Seconds, Minutes, Hours, Days, Date,

   Months, and Years with Automatic Leap-Year

   Compensation Valid Up to the Year 2100

■ 2M x 8 NV SRAM

■ Watch Function is Transparent to RAM Operation

■ Automatic Data Protection During Power Loss

■ Unlimited Write-Cycle Endurance

■ Surface-Mountable BGA Module Construction

■ Over 10 Years of Data Retention in the Absence of

   Power

■ Battery Monitor Checks Remaining Capacity Daily

■ +3.3V Operation

■ Underwriters Laboratory (UL) Recognized

   (www.maxim-ic.com/qa/info/ul/)

APPLICATIONS

   Telecom Switches

   Routers

   RAID Systems