Analysis of metastability errors in asynchronous SAR ADCs

Previous work has provided detailed analysis of metastability errors and SMR for synchronous SAR ADC. This work extends the analysis to the Asynchronous SAR (ASAR), for which metastability errors are more difficult to understand and quantify. Since the relationship between SMR and conversion time cannot be reduced to a closed-form solution, a framework is instead provided for using numerical simulation results to determine the necessary conversion time such that metastability errors will not limit resolution. Two main contributions are made using this framework: first, the designer may determine the maximum effective sample rate for the ADC (and therefore the speed benefit over the synchronous SAR); second, it is shown that proximity detectors are not effective solutions to improving metastability performance.