RV-3149-C3 is a CMOS low power, real-time clock/calendar module with built-in Thermometer and Digital Temperature Compensation circuitry (DTCXO). The temperature compensation circuitry is factory-calibrated and greatly improves the time accuracy by compensating the frequency-deviation @ 25°C and the anticipated frequency-drift over the temperature of the embedded 32.768 kHz “Tuning-Fork” crystal, even over the extended Temperature Range -40°C to +125°C. Data is transferred serially via a SPI interface with a maximum SCL clock frequency in fast mode of 1 MHz, the built-in word address register is incremented automatically after each written or read data byte. Beyond standard RTC-functions like year, month, day, weekday, hours, minutes, seconds information, the RV-3149-C3 offers highly versatile Alarm and Timer-Interrupt function, programmable Clock-Output and Low-Voltage Detector.


  • RTC module with built-in “Tuning Fork” crystal oscillating at 32.768 kHz
  • Factory calibrated, all built-in Temperature Compensation circuitry
  • Time accuracy: Temperature Range
    • 25°C +/- 3 ppm 
    • 0°C to + 50°C +/- 4 ppm 
    • -10°C to + 60°C +/- 5 ppm 
    • -40°C to + 85°C +/- 6 ppm 
    • -40°C to +125°C +/- 8 ppm
  • Ultra low power consumption: 800nA typ @ VDD = 3.0V / Tamb = 25°C
  • Wide clock operating voltage: 1.3 – 5.5V
  • Extended operating temperature range: -40°C to +125°C
  • SPI serial interface with fast mode SCL clock frequency of 1 MHz
  • Provides year, month, day, weekday, hours, minutes and seconds
  • Main Power Supply to Backup Battery switchover circuitry with Trickle Charger
  • Programmable CLKOUT pins for peripheral devices (32.768 kHz / 1024 Hz / 32 Hz / 1 Hz)

Block Diagram


The unique features make this product perfectly suitable for many applications:

  • Automotive: Car Radio / GPS and Tracking Systems / Dashboard / Engine Controller /
  • Car Mobile & Entertainment Systems / Tachometers
  • Metering: E-meter / Heating Counter
  • Outdoor: ATM & POS systems / Surveillance & Safety systems / Ticketing system
  • All kind of portable and battery operated devices
  • Industrial and consumer electronics
  • White goods


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