A Dynamic Tracking Algorithm Based SAR ADC in Bio-Related Applications

This paper presents a novel dynamic tracking algorithm to boost the energy quality of successive approximation register analog-to-digital converter (ADC) in bio-related applications. By introducing two tracking windows that are adjacent to prediction interval, the proposed algorithm can track down the input signal's variation range, automatically adjust the subrange interval, and then update prediction code. The 12-bit ADC is designed in a 0.13-μm CMOS process with a 0.6-V supply. Given a 41.5-Hz sinusoid signal, the proposed ADC exhibits 11.77 effective number of bit and 85.4-dB spur-free dynamic range at 10-kHz sample rate with a power consumption of 960 nW. Given an electrocardiogram (ECG) signal with baseline drift and vibrations, the ADC achieves 94.42% prediction accuracy. Also, dynamic tracking method provides an approach of ECG feature extraction in time domain.