A 3.2mW SAR-assisted CTΔ∑ ADC with 77.5dB SNDR and 40MHz BW in 28nm CMOS

Sigma (CTΔΣ) ADC, which combines the energy efficiency of SAR ADCs with the relaxed driving requirements of CTΔΣ ADCs, as well as similar anti-alias filtering. When clocked at 2.4GHz, the ADC achieves 77.5dB SNDR in 40MHz BW. It consumes 3.2mW, resulting in a state-of-the-art Walden FoM of 6.5fJ/cs and a Schreier FOM of 178.5dB.