Use the offset and full-scale (gain) registers to correct ADC error. As shown in Figure 9-51, the value of the offset calibration register is subtracted from the filter output and then multiplied by the full-scale register value divided by 400000h. The data are then clipped to a 32-bit value to provide the final output.
Equation 22 shows the internal calibration. ADC2 calibration registers are 16 bit. For ADC2, the ADC2FSC[1:0\} registers are for full-scale calibration and the ADC2OFC[1:0] registers are for offset calibration.