DC offset cancel in a conventional A/D converter is conducted by inputting two analog signals serving as references, detecting a DC offset error and a gain error of A/D conversion, and canceling the errors in digital processing in a subsequent stage.
However, the above-described conventional technique has a problem that two different reference analog signals are needed. Furthermore, precisions are required of the two different reference analog signals. In addition, there is a problem of an error of the A/D converter involving single-ended to differential conversion, when conducting single-ended to differential conversion on an input signal.