A New Analog-to-Digital Converters Differential Nonlinearity Testing Method

This paper presents a new approach to static parameters testing of analog-to-digital converters (ADCs). 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 succesive 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 sawtooth 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 12b ADC obtained by new method are compared with common static method results.