A Segmented SAR/SS ADC with Digital Error Correction and Programmable Resolution for Column-Parallel Sensor Arrays

We introduce a programmable segmented ADC for column-parallel sensor arrays, which performs a successive approximation algorithm followed by a single-slope conversion. The circuit implements digital error correction using sub-binary capacitor weighting and crossover redundancy. The arrangement re-uses one dynamic comparator between the two phases, and uses a new capacitor switching protocol which reduces the required capacitor area. A prototype was designed and fabricated in 0.18μm CMOS, which occupies an area of 0.012mm², and achieves 56.55 dB SNR and 52.5 fJ/conv.