ファントムクロック付き、2M x 8 NV SRAM



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-of-tolerance 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.

The phantom clock provides timekeeping information including hundredths of seconds, seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The phantom clock operates in either 24-hour or 12-hour format with an AM/PM indicator.

Because the DS1254 has a total of 168 balls and only 35 active signals, balls are wired together into groups, thus providing redundant connections for every signal.
DS1254、DS1254W、DS1254Y:標準動作回路 DS1254、DS1254W、DS1254Y:標準動作回路 拡大表示+


  • 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


  • RAIDシステム
  • ルータ/スイッチ
  • テレコム交換機
製品の信頼性レポート: DS1254W.pdf 
デバイス   ウェハープロセス   プロセス技術   サンプルサイズ   不合格   FIT (25°C)   FIT (55°C)   Material Composition  

注: 不良率はプロセス技術ごとにまとめられ、関連する型番にマッピングされます。 不良率はテストされたユニット数に大きく依存します。

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±5ppm, I2C Real-Time Clock with Integrated MEMS Oscillator

  • Highly Accurate RTC with Integrated MEMS Resonator Completely Manages All Timekeeping Functions
  • 64-Byte RAM for User Data Storage
  • Simple Serial Interface Connects to Most Microcontrollers