The maximum value of the current-sense resistor is calculated based on choice of gain, value of the maximum current the be sensed (IMAX), and the power supply voltage (VS). When operating at the maximum current, the output voltage must not exceed the positive output swing specification, VSP. For the given design parameters, the maximum value for RSENSE calculated in Equation 6 is 1.321 kΩ.
However, because this value exceeds the maximum recommended value for RSENSE, a resistance value of 1 kΩ must be used. When operating at the minimum current value, IMIN the output voltage must be greater than the swing to GND (VSN), specification. For this example, the output voltage at the minimum current (VOUTMIN) calculated in Equation 7 is 25 mV, which is greater than the value for VSN.