A calibration-free 2.3 mW 73.2 dB SNDR 15b 100 MS/s four-stage fully differential ring amplifier based SAR-assisted pipeline ADC

A four-stage fully differential ring amplifier in 40 nm CMOS improves gain to over 90 dB without compromising speed. It is applied in a 15b, 100 MS/s calibration-free SAR-assisted pipeline ADC. In addition, a new auto-zero noise filtering method reduces noise without consuming additional power. The ADC achieves 73.2 dB SNDR (11.9b) and 90.4 dB SFDR with a 1.1 V supply. It consumes 2.3 mW resulting in a SNDR based Schreier FoM of 176.6 dB.