Efficient detection of metastability events in asynchronous SAR ADCs

A new approach is proposed to deal with the metastability errors in asynchronous SAR ADCs. This proposal avoids the disadvantages of conventional metastability detectors (additional metastability events due to the detector itself,  lowness from additional comparator loading, additional logic delays, need to perform detection on each bit), but provides a significant decrease in metastability errors and their amplitudes. The approach uses both comparators’ outputs to detect whether metastability occurred at all during conversion (without determining in which particular bit). Theoretical examination and Octave simulation show that this information suffices to correct half of metastability errors.