Examples are provided for a method and apparatus for calibration of an analog-to-digital converter (ADC) including multiple sub-ADCs. The method includes applying a calibration signal to an input node of each sub-ADC. For each sub-ADC, a corresponding error signal is generated based on output signals of the sub-ADC and a reference sub-ADC. Each sub-ADC is calibrated based on the corresponding error signal. The reference sub-ADC is selected by: applying a non-zero input voltage signal to the input node of each sub-ADC, measuring a corresponding output signal of each sub-ADC in response to the non-zero input voltage signal, generating a deviation error based on a subtraction of a stored value from the measured output signal of each sub-ADC, and designating as the reference sub-ADC a sub-ADC from the multiple sub-ADCs based on the deviation error.