The INAx191 provides accurate current measurements over a wide dynamic range. The high accuracy of the device is attributable to the low gain error and offset specifications. The offset voltage of the INAx191 is less than 12 µV. In this case, the low offset improves the accuracy at light loads when VIN+ approaches VIN–.
Another advantage of low offset is the ability to use a lower-value shunt resistor that reduces the power loss in the current-sense circuit, and improves the power efficiency of the end application.
The maximum gain error of the INAx191 is specified to be within 0.25% for most gain options. As the sensed voltage becomes much larger than the offset voltage, the gain error becomes the dominant source of error in the current-sense measurement. When the device monitors currents near the full-scale output range, the total measurement error approaches the value of the gain error.