Measurement Ranges and Accuracy

The XAM has four measurement ranges. These are defined by two shunt resistors and two gain stages.

Table 1. XAM Measurement Ranges and Accuracy
Measurement Range Hardware Resolution Accuracy Comments
Range 1 Low current shunt and high gain stage 20 nA 1 LSB ±1% Accuracy will decrease below 1μA. Typical accuracy for 300nA is 1 LSB ± 10%.
Range 2 Low current shunt and low gain stage 150 nA 1 LSB ±1%
Range 3 High current shunt and high gain stage 10 μA 1 LSB ±1%
Range 4 High current shunt and low gain stage 100 μA 1 LSB ±1% Accuracy will decrease above 100 mA. Typical accuracy is 1 LSB ±5% at 400 mA. Maximum current is 400 mA.

The ranges are automatically switched by the XAM to achieve the best measurement results and the currently active range is visualized in the Data Visualizer front-end tool. The maximum voltage drop over the shunt resistor is 100 mV, and the XAM switches the range automatically before reaching this limit.