A 80-dB DR, 10-MHz BW continuous-time sigma-delta modulator with low power comparators and switch drivers

A third-order multi-bit feedforward-feedback (FF-FB) mixed continuous time sigma-delta modulator (CTSDM) for WLAN receivers is presented. The comparators and switch drivers are simplified and therefore can be more power-efficient. The FF-FB mixed architecture obtains a signal transfer function (STF) with little out-of-band peaking. Based on the signal bandwidth and anti-aliasing requirements for the WLAN receivers, we realized the modulator with SMIC 0.18um CMOS Mixed Signal process and the core achieves 80dB SNR over 10MHz signal bandwidth while consuming 30mW at 1.8V supply.