A 99.43% Energy Saving Switching Scheme with Asymmetric Binary Search Algorithm for SAR ADCs

In this paper, a low-energy switching scheme based on the asymmetric binary search algorithm for successive approximation register (SAR) analog-to-digital converters (ADCs) is proposed. To reduce switching energy and area, the proposed scheme uses the single-side switching method and the least significant bit (LSB) capacitor is split into two one-half unit capacitors. Using the series capacitance scheme, the capacitance mismatch caused by process deviation is effectively improved. Compared with the conventional switching method, the switching energy of this scheme is decreased by 99.43% and the area is saved by 87.2%. MATLAB simulation results show that this scheme also has a low nonlinearity that the maximum differential nonlinearity is only 0.37 LSB and the maximum integral nonlinearity is only 0.43 LSB.