A 170.7-dB FoM-DR 0.45/0.6-V Inverter-Based Continuous-Time Sigma–Delta Modulator

摘要

This brief presents a low-voltage inverter-based continuous-time sigma-delta modulator (CT-SDM). The inverter-based amplifiers are single-stage and their operating point is provided by a bulk-based current mirror. To improve the power-efficiency, a passive RC path is used to assist the amplifier of the first integrator. The proposed modulator was fabricated in a 180-nm CMOS process with an active area of 0.36 mm(2). The modulator loop filter operates with a supply voltage of 0.45 V while the digital circuitry operates at 0.6 V. The modulator total power consumption is 28.72 mu W. For a 50-kHz signal bandwidth, the measured peak SNR/SNDR is 71.24/70.64 dB and the achieved DR is 78.3 dB, leading to a Schreier figure-of-merit of 170.70 dB.