Single Phase Multifunction Energy Metering IC with SPI Interface


  • Bidirectional active and reactive power/energy measurement
  • RMS voltage and frequency measurement
  • SPI communication bus
  • Meets the IEC 61036 Specification requirements for Class 1 AC Watt hour meters
  • Meets the IEC 61268 Specification requirements for Class 2 AC VAR hour meters
  • Protected against ESD
  • Total power consumption rating below 25mW
  • Adaptable to different current sensor technologies
  • Operates over a wide temperature range
  • Precision on-chip voltage reference
  • Measures AC inputs only


The SA9903B is a single phase bidirectional energy/power metering integrated circuit that has been designed to measure active and reactive energy, RMS mains voltage and mains frequency. The SA9903B has an integrated SPI serial interface for communication with a microcontroller. Measured values for active and reactive energy, the mains voltage and frequency are accessible through the SPI interface from 24 bit registers. The SA9903B active and reactive energy registers are capable of holding at least 52 seconds of accumulated energy at full load. A mains voltage zero crossover is available on the FMO output.

The SA9903B includes all the required functions for single phase power and energy measurement such as oversampling A/D converters for the voltage and current sense inputs, power calculation and energy integration. This innovative universal single phase power/energy metering integrated circuit is ideally suited for energy calculations in applications such as electricity dispensing systems, residential metering and factory energy metering and control.

The SA9903B integrated circuit is available in a 20 pin small outline (SOIC20) RoHS compliant package.