Extending the servo-loop for ADC transition level measurements under dynamic input conditions

For high-resolution Nyquist-rate ADCs, testing the linearity of the transfer characteristic at all-codes becomes very time consuming as the number of codes increases exponentially with resolution. Previously, a model-based test approach has been proposed based on measurements using a servo-loop. With the servo-loop, the ADC linearity is tested under static input conditions by measuring only a small subset of code transition levels. Adopting this short-codes approach, we propose a faster settling servo-loop implementation. We extend the servo-loop and the model-based short-codes test to linearity testing under dynamic input conditions.