Session 23-2

A Low Power Sigma-Delta Modulator Using Class- C Inverter

 

Abstract

In switched capacitor sigma-delta analog-to-digital converters (ADCs), an operational transconductance amplifier (OTA) is the main building block and consumes most of power. This paper proposes that the OTAs can be replaced with class-C inverters for low-power consumption without sacrificing the performance. A second order sigma-delta modulator using class-C inverter technique is fabricated with a 0.35-um CMOS process, occupies 0.00324 mm2, dissipates 5.6-uW under 1.2V supply-voltage, and provides 63-dB/72-dB/76-dB SNDR/SNR/DR over 8-kHz signal bandwidth.