Analog Devices DS1248 Product Info

• Real-Time Clock (RTC) Keeps Track of Hundredths of Seconds, Minutes, Hours, Days, Date of the Month, Months, and Years
• 128k 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
• Full 10% Operating Range
• Over 10 Years of Data Retention in the Absence of Power
• 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
• PowerCap Module Board Only
  • Surface Mountable Package for Direct Connection to PowerCap Containing Battery and Crystal
  • Replaceable Battery (PowerCap)
  • Pin-for-Pin Compatible with DS1244P and DS1251P

The DS1248 1024K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 128K words by 8 bits) with a built-in real-time clock. The DS1248 has a self-contained lithium energy source and control circuitry, which constantly monitors V_CC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and writes protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock.