DS1742

Y2KC不揮発性タイムキーピングRAM


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説明

The DS1742 is a full-function, year 2000-compliant (Y2KC), real-time clock/calendar (RTC) and 2k x 8 nonvolatile static RAM. User access to all registers within the DS1742 is accomplished with a bytewide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the day of the month and leap year are made automatically.

The RTC clock registers are double-buffered to avoid access of incorrect data that can occur during clock update cycles. The double-buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1742 also contains its own power-fail circuitry, which deselects the device when the VCC supply is in an out-of-tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCC as errant access and update cycles are avoided.
DS1742:ブロックダイアグラム DS1742:ブロックダイアグラム 拡大表示+

主な特長

  • Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit and Lithium Energy Source
  • Clock Registers are Accessed Identically to the Static RAM; These Registers are Resident in the Eight Top RAM Locations
  • Century Byte Register
  • Totally Nonvolatile with Over 10 Years of Operation in the Absence of Power
  • BCD Coded Century, 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% VCC Power Supply Tolerance
  • Lithium Energy Source is Electrically Disconnected to Retain Freshness until Power is Applied for the First Time
  • Standard JEDEC Bytewide 2k x 8 Static RAM Pinout
  • Quartz Accuracy ±1 Minute a Month at +25°C, Factory Calibrated

技術資料

チュートリアル 5791 Tips for Writing Bulletproof Real-Time Clock Control Code
チュートリアル 5413 State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks
アプリケーションノート 5013 マキシム製品におけるリチウムバッテリ
アプリケーションノート 519 Using a Nonvolatile Timekeeping RAM with a Microcontroller
アプリケーションノート 504 Design Considerations for Maxim Real-Time Clocks

品質および環境データ

製品の信頼性レポート: DS1742.pdf 
鉛フリーパッケージの錫(Sn)のウィスカレポート

その他リソース

RTCの計算
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)  

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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