A Comprehensive Digital Calibration Method for Pipeline SAR ADCs Using Extended Kalman Filter

This paper presents a fully digital foreground calibration method for pipeline-SAR analog-to-digital converters (ADCs) using sine-fit based on the Extended Kalman Filter (EKF). The sine-fit technique provides a reference output, while an adaptive Least Mean Square (LMS) algorithm iteratively adjusts the reconstruction weights to correct mismatches and nonlinearities. The EKF significantly reduces hardware complexity by enabling real-time estimation without requiring extensive data storage. A modeled 12-bit pipeline-SAR ADC is used to evaluate the method's effectiveness. Simulation results demonstrate that the proposed calibration scheme improves the spurious-free dynamic range (SFDR) and signal-to-noise-and-distortion ratio (SNDR) by 33.6 dB and 18.8 dB, respectively.