A Chopper Negative-R Delta-Sigma ADC for Audio MEMS Sensors

This paper presents a proposed low-noise and high-sensitivity Internet of Thing (IoT) system based on an M&NEMS; microphone. The IoT device consists resistive accelerometer associated with electronic readout circuit, which is silicon nanowire Continuous-Time (CT) Δ Σ ADC. first integrator the ADC positive feedback DC-gain enhancement two-stage amplifier due to its high linearity operations. To mitigate both offset 1/f noise, suggested delay-time chopper negative-R stabilization technique applied around integrator. A 65-nm CMOS process implements CT Δ Σ supply voltage circuit 1.2-V while 0.96-mW power consumption 0.1-mm2 area. microphone complete are fabricated measured. Over working frequency bandwidth 20-kHz, measurement results reach signal noise ratio (SNR) 102.8-dB. Moreover, it has measured dynamic range (DR) 108-dB distortion (SNDR) 101.3-dB.