Microchip – MCP39F521: I2C Power Monitor with Calculation and Energy Accumulation

Analog Signal Chain
The MCP39F521 is a highly integrated, single-phase power-monitoring IC designed for real-time measurement of input power for AC/DC power supplies, providing power and energy values.

It includes dual-channel delta sigma ADCs, a 16-bit calculation engine, EEPROM and a flexible 2-wire interface. An integrated low-drift voltage reference in addition to the 94.5dB of SINAD performance on each measurement channel allows for better than 0.1% accurate designs across a 4000:1 dynamic range.


  • 0.1% error across 4000:1 dynamic range
  • 64-bit wide import and export active energy accumulation registers
  • 64-bit four quadrant reactive energy accumulation registers
  • I2C interface, up to 400kHz clock rate
  • Dedicated PWM output pin
  • Fast calibration routines
  • Built-in calculations for active and reactive energy accumulation
  • Signed active and reactive power outputs
  • 512bytes user-accessible EEPROM
  • Dedicated zero crossing detection (ZCD) pin
  • Automatic event pin control through fast voltage surge detection