NXP’s automotive realtime clocks are designed for highest reliability and lowest power consumption. Devices are available with I2C or SPI bus interfaces.

Timing devices

Specifically designed for automotive applications – such as instrument cluster, tachographs, black boxes for electronic road pricing, battery management units and car radios – our automotive realtime clocks use a 32.768kHz oscillator and one oscillator capacitor. The only additional external components required are a 32.768kHz quartz crystal and a capacitor connected to the OSCI pin. They provide year, month, day, weekday, hours, minutes and second information and feature programmable alarm and timer functions with interrupt capability. They have an extended operating temperature range of up to 125 ºC and AEC-Q100 automotive compliant qualification.


  • Extended operating temperature range from -40ºC to +125ºC
  • Extended operating temperature range to +125 ºC to withstand harshest conditions
  • Wide power supply voltage range from 1.6V/1.8V to 5.5V
  • Automotive AEC-Q100 compliant qualification for highest reliability and robustness
  • Low power consumption (0.55 / 0.65 μA at VDD = 3.0 V and Tamb = 25 °C)
  • Low power consumption to enable power critical applications
  • I2C or SPI interface
  • Programmable alarm and timer functions with interrupt capability
  • One integrated oscillator capacitor
  • Programmable clock output to drive peripheral devices

Target Applications

  • Instrument clusters
  • Tachographs
  • Black boxes for electronic road pricing
  • Battery management units
  • Car radios

Product Order Description
PCA21125T SPI-bus Real-Time Clock and calendar
PCA2129T Automotive accurate RTC with integrated quartz crystal