A method of operating a built-in self-test (BIST) device for testing a successive approximation register analog-to-digital converter (SAR ADC), the method comprising:
- storing first and second output codes in response to first and second input voltages;
- outputting a gain error based on a calculation result of a difference between the stored first and second output codes and a first normal code according to the second input voltage;
- storing third and fourth output codes in response to the second input voltage and the third input voltage;
- outputting an offset error based on a calculation result of the stored third output code and the first normal code;
- and
- outputting an integral non-linearity (INL) error based on a calculation result of a difference between the stored third and fourth output codes and a second normal code according to the third input voltage,
- wherein the SAR ADC receives a signal corresponding to the offset error from the BIST device and outputs an offset-corrected digital signal.