Measurement method and apparatus for ADC calibration

摘要

An uncalibrated converter element in an analog-digital converter may be replaced with two or more smaller elements having an effective total net value that is equal to that of the uncalibrated converter element. In an exemplary case where the element is capacitor, one or more of these smaller capacitors may be independently calibrated by switching the smaller capacitor between two voltages, such as a reference voltage and ground, and then calculating a difference of corresponding digital output codes generated by the backend ADC with previously calibrated capacitors associated with lesser significant bits. The total capacitance of the uncalibrated capacitor may be apportioned between the smaller capacitors so that the individual maximum charge contribution of each smaller capacitor to the converter output together with any expected manufacturing variance does not exceed the aggregated contribution of the previously calibrated capacitors.