A Single-Channel 2-GS/s 8-bit Two-Step SAR ADC in 28nm CMOS

This paper presents a single-channel 8-bit 2 GS/s two-step successive approximation register (SAR) analog-to-digital converter (ADC). Combined with the passive residue transfer and comparators alternation technology, the proposed SAR ADC is currently one of the fastest single-channel 8-bit SAR ADCs, and its performance is superior to time-interleaved SAR ADCs at the same resolution and sampling rate. The proposed ADC in 28-nm CMOS consumes 6.91 mW at 2 GS/s with a 1V supply. It achieves a Nyquist SNDR of 45.6 dB and results in an FoM of 22.2 fJ/conv.-step.