A new approach in differential nonlinearity testing of the analog-to-digital converters

In the paper, a new approach to static parameters testing of analog-to-digital converters (ADCs) is presented. In comparison to ordinary approaches, the measured transition levels are not related to zero potential but to the transition levels of a reference ADC, which is of the same type as a tested ADC. These differences, which can be in the extreme case in the range of a few least significant bits (LSB) of the tested ADC, were measured by a successive approximation principle-based test system, with a digital-to-analog converter (DAC) in the feedback. A special algorithm has been proposed to control the measurement. The new approach sets no special requirements on the input saw-tooth impulse generator precision, and the precision of the obtained differential non-linearity (DNL) characteristics mainly depends on the DAC used. Practical measurement results evaluated on data acquisition board Lab-PC-1200 with 12 bit ADC obtained by new method are compared with the common static method results.