The INA4230 integrates a low offset 16-bit delta-sigma (ΔΣ) ADC. This ADC is multiplexed for each channel to process both the shunt voltage and bus voltage measurements. Bus voltage measurements are made with respect to IN- and GND. The shunt voltage measurement is a differential measurement of the voltage developed when the load current flows through a shunt resistor between the IN+ and IN– pins for each channel. The shunt voltage measurement has a maximum offset voltage of only 75µV and a maximum gain error of 0.75%. The low offset voltage of the shunt voltage measurement allows for increased accuracy at light load conditions for a given shunt resistor value. Another advantage of low offset is the ability to sense a lower voltage drop across the sense resistor accurately, thus allowing for a lower-value shunt resistor. Lower-value shunt resistors reduce power loss in the current-sense circuit and help improve the power efficiency of the end application.

There are no special considerations for power-supply sequencing because the bus common-mode at the IN+ and IN- pins and power-supply voltage at the VS pin are independent of each other; therefore, the bus common-mode voltage can be present with the supply voltage off, and so forth.