An apparatus for determining one or more calibration values of an ADC is configured to receive a first reference signal and a second reference signal and apply to the ADC the following: over a first signal application period, a first ADC input signal including the first reference signal; over a second signal application period, a second ADC input signal having a substantially equal magnitude and an inverse polarity to the first ADC input signal; over a third signal application period, a third ADC input signal including the second reference signal; and over a fourth signal application period, a fourth ADC input signal having a substantially equal magnitude and an inverse polarity to the third ADC input signal. The apparatus is configured to determine the one or more calibration values based, at least in part, on an ADC output signal of the ADC over the four signal application periods.