In this system example, the value of VVREF is 3.3 V with a sense current from 0 to 40 A. The linear range of the SOx output for the DRV8353x device is 0.25 V to VVREF – 0.25 V (from the VLINEAR specification). The differential range of the sense-amplifier input is –0.3 to +0.3 V (VDIFF).
Therefore, the gain setting must be selected as 20 V/V or 40 V/V and the value of the sense resistor must be less than 3.75 mΩ to meet the power requirement for the sense resistor. For this example, the gain setting was selected as 20 V/V. The value of the resistor and worst-case current can be verified that R < 3.75 mΩ and Imax = 40 A does not violate the differential range specification of the sense amplifier input (VSPxD).