Real-time measurement of ac power gets a new weapon in the arsenal with Microchip’s MCP39F501 power-monitoring IC. The single-phase device includes two 12-bit delta-sigma analog-to-digital converters (ADCs), a 16-bit calculation engine, EEPROM, and a flexible two-wire interface. Accuracy of 0.1% error across a 4000:1 dynamic range is attributed to an integrated low-drift voltage reference and 94.5 dB of signal-to-noise and distortion ratio (SINAD) performance. Built-in calculations include active, reactive and apparent power, rms current and voltage, line frequency, power factor, and programmable event notifications. Operating temperature ranges from −40 to +125°C. The chip comes in a 5- by 5-mm, 28-lead QFN package. Among its applications are server and networking power supplies, power distribution units, and lighting systems in the commercial sector; appliances and smart plugs in the consumer market; and industrial power meters and equipment.