CMOS ADCs Towards 100 GS/s and Beyond

The implementation of a 64x time-interleaved ADC in 32nm CMOS SOI is analyzed. Measurement results confirm 33 dB SNDR up to 19.9 GHz at 90 GS/s and 1.2V supply. Architecture details and analysis show insights into limitations and potentials of the chosen architecture. In par-ticular the input bandwidth is of concern for ADCs at more than 64 GS/s, as a larger number of sampling switches in-creases the parasitic load and reduces the input bandwidth. Insights on a simplified analysis of interleaver structures and existing solutions to bandwidth issues are highlighted and show a path to extend the sampling speed of CMOS ADCs beyond 100 GS/s.