A 75dB DR 50MHz BW 3rd order CT-ΔΣ modulator using VCO-based integrators

Abstract

A wide bandwidth, high sample rate 3rd order continuous-time ΔΣ modulator using VCO-based integrators is presented. Non-idealities caused by VCOs at the modulator frontend are addressed using both circuit- and architecture-level techniques. Fabricated in 65 nm CMOS, the prototype modulator operates at 1.28 GS/s and achieves a dynamic range of 75 dB, SNR of 71 dB in 50 MHz bandwidth, while consuming 38 mW of total power.