SLYS021A January 2021 – May 2022 INA228
The shunt calibration register needs to be correctly programmed at each VS power up in order for the device to properly report any result based on current. The first step in properly setting this register is to calculate the LSB value for the current by using Equation 3. Applying this equation with the maximum expected current of 10 A results in an LSB size of 19.0735 μA. Applying Equation 2 to the CURRENT_LSB and selected value for the shunt resistor results in a shunt calibration register setting of 4050d (FD2h). Failure to set the value of the shunt calibration register will result in a zero value for any result based on current.