The present application discloses an ADC (10). The ADC has an A/D conversion operation mode and a measurement operation mode. The ADC includes an input terminal (100), a DAC (104), and an output terminal (102). The input terminal is configured to receive an analog signal. The output terminal is configured to output a digital signal. The DAC includes a plurality of D/A conversion units. When the ADC operates in the A/D conversion operation mode, the ADC is configured to convert the analog signal into the digital signal, and when the ADC operates in the measurement operation mode, the digital signal related to a ratio of a capacitance of the D/A conversion unit to be measured to a total capacitance of the plurality of D/A conversion units.