A 12-Bit Dynamic Tracking Algorithm-Based SAR ADC With Real-Time QRS Detection

Abstract

A 12-bit successive approximation register (SAR) ADC based on dynamic tracking algorithm and a real-time QRS-detection algorithm are proposed. The dynamic tracking algorithm features two tracking windows which are adjacent to prediction interval. This algorithm is able to track down the input signal's variation range and automatically adjust the subrange interval and update prediction code. QRS-complex detection algorithm integrates synchronous time sequential ADC and realtime QRS-detector. The chip is fabricated in a standard 0.13 μm CMOS process with a 0.6 V supply. Measurement results show that proposed ADC exhibits 10.72 effective number of bit (ENOB) and 79.63 dB spur-free dynamic range (SFDR) at 10k Hz sample rate given 41.5 Hz sinusoid input. The DNL and INL are bounded at -0.6/0.62 LSB and -0.67/1.43 LSBs. The ADC achieves FoM of 48 fJ/conversion-step at the best case. Also, the prototype is experimented with ECG signal input and extracts the heart beat signal successfully.