Demonstration circuit 2156A features the LTC2946 rail-to-rail system monitor that measures current, voltage, power, energy and charge. It features an operating range of 2.7V to 100V and includes a shunt regulator for operation from supplies above 100V to allow flexibility in the selection of input supply. The current measurement range of 0V to 100V is independent of the input supply. An onboard, 0.4% accurate, 12-bit ADC measures load current, input voltage and an auxiliary external voltage. A 24-bit power value is generated by digitally multiplying the measured 12-bit load current and input voltage data. Energy and charge data are generated by integrating power and current. Minimum and maximum values are stored and an overrange alert with programmable thresholds minimizes the need for software polling. Data is reported via a standard I2C interface. Shutdown mode reduces power consumption to 20μA.