RV-3129-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 an I²C interface with a maximum SCL clock frequency in fast mode of 400 kHz, 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-3129-C3 offers highly versatile Alarm and Timer-Interrupt function, programmable Clock-Output and Low-Voltage Detector.