Both monitors use an external sense resistor to determine current by measuring voltage differences. The internal 12‑bit ADC amplifies and digitises the voltage, and can also simultaneously sample primary and auxiliary input voltage.
The internal digital block performs multiplication of the current and primary input voltage to calculate power, and the devices feature a power accumulator to meter energy. An industry-standard PMBus interface enables a master controller to read back the data from the device.
The master controller combines the information with a known sense resistor value to calculate the current, voltage, power, and energy consumption over time on the monitored rail.
The ADM1293 and ADM1294 Digital Power Monitors are rated for -40°C to 125°C. The ADM1293 is designed for high-side supply monitoring (0V to 20V), and the ADM1294 is designed for low-side supply monitoring (-48V to 0V, with integrated shunt regulator).