SNOSC63B February 2012 – December 2014 LMP8646
PRODUCTION DATA.
The accuracy of the current measurement also depends on the value of the shunt resistor RSENSE. Its value depends on the application and is a compromise between small-signal accuracy and maximum permissible voltage loss in the load line.
RSENSE is directly proportional to VSENSE through the equation RSENSE = (VSENSE) / (ISENSE). If VSENSE is small, then there is a smaller voltage loss in the load line, but the output accuracy is worse because the LMP8646 offset error will contribute more. Therefore, high values of RSENSE provide better output accuracy by minimizing the effects of offset, while low values of RSENSE minimize the voltage loss in the load line. For most applications, best performance is obtained with an RSENSE value that provides a VSENSE of 100 mV to 200 mV.