Split-Delta Background Calibration for SAR ADCs

This brief introduces a unified performance benchmarking framework that allows us to map existing successive approximation register mismatch calibration methods and compare their performance under identical circumstances. Using this framework, an analysis of advantages and disadvantages of popular state-of-the-art methods is presented. Combining the strengths of some of these methods leads to the proposal of a new calibration scheme, which we call the split-delta method. This calibration approach is a modification of the split ADC yet avoids the more complex architectural modifications required by other split-ADC schemes while preserving good convergence speed and performance. Finally, the effects that the dynamic effects on top of capacitor mismatch and offset have on the converter's signal-to-noise ratio are analyzed.