TIDUF27A February 2025 – March 2025 AMC131M03 , MSPM0G1507
While AMC131M03 is used four times on the PCB, the 2-channel version AMC131M02 suffices, in case only current and voltage are to be measured. The 3rd channel in AMC131M03 (not present in AMC131M02) can support a temperature measurement at the shunt sensor, if required.
The choice of voltage divider resistors for the voltage channel is selected to make sure the main voltage is divided down to adhere to the normal input range of the AMC131M03 device. Since this stand-alone ADC has a large dynamic range but only a small range is needed to measure voltage, the voltage front-end circuitry is purposely selected so that the maximum voltage present at the inputs of the voltage channel ADCs are only a fraction of the full-scale voltage. By reducing the voltage fed to the AMC131M03 voltage input channels, voltage-to-current crosstalk, which actually affects metrology accuracy more than voltage ADC accuracy, is reduced at the cost of voltage accuracy, thereby resulting in more accurate energy measurements at lower currents.