This paper reports a new approach for debugging of the analog to digital converters based on process monitoring and extended design-for-test implementation. The circuit is reconfigured in such a way that all subblocks are analysed and tested for their full input range allowing full observability and controllability of the analog to digital converter. To set initial data, estimate the parameter update and to guide the test, dedicated monitors have been designed. Additionally, the second presented algorithm allow circuit calibration without explicit need for any dedicated test signal nor requires a part of the conversion time. It works continuously and with every signal applied to the ADC.