The INAx290 measures the differential voltage developed by current flowing through a resistor that is commonly referred to as a current-sensing resistor or a current-shunt resistor. Figure 7-3 shows that the INAx290 operates in unidirectional mode only, meaning the device only senses current sourced from a power supply to a system load.

Figure 7-3 Unidirectional Application (Single-Channel Device)

The linear range of the output stage is limited to how close the output voltage can approach ground under zero-input conditions. The zero current output voltage of the INAx290 is very small, with a maximum of GND + 25 mV. Apply a sense voltage of (25 mV / Gain) or greater to keep the INAx290 output in the linear region of operation.