A 100.2-dB SNDR Active-Passive Continuous-Time ΔΣ Modulator With Calibrated Negative-R

This paper presents a high-precision active-passive continuous-time Delta-Sigma Modulator (CTDSM) based on negative-R compensation technology, with a passive integrator in its first stage. Negative-R is used to alleviate the limitations of passive integrator in high-precision CTDSM applications, including integration pole drift, load effect, gain attenuation. Furthermore, in order to improve the robustness of negative-R in the integrator, an analog calibration technique is proposed. The transistor-level prototype is implemented in 180nm CMOS and the simulation results show that the proposed modulator’s signal-to-noise and distortion ratio (SNDR) is 100.2dB over a bandwidth (BW) of 24kHz, with a FoMs value of 179.4 dB.