A 0.8-/spl mu/W switched-capacitor sigma-delta modulator using a class-C inverter

An ultra low power second-order switched capacitor (SC) sigma-delta (/spl Sigma//spl Delta/) modulator is presented. Using of a class-C inverter instead of an operational transconductance amplifier (OTA) enables the SC /spl Sigma//spl Delta/ modulator to achieve sub-/spl mu/W power consumption. The proposed modulator has been implemented using a 0.35/spl mu/m CMOS process. The measured peak SNR of the modulator is 56dB in a 3kHz signal bandwidth with sampling frequency of 200kHz. Its dynamic range is approximately 56 dB and the power consumption is only 0.8/spl mu/W with a 1V power supply.