An 88dB 48 KHz full feed-forward sigma-delta modulator

Abstract

This paper examines the design of full feed-forward sigma-delta modulator which is much more suitable for the CMOS digital process with low supply voltage than the traditional second-order feedback loop. The full feed-forward system reduces the modulator's sensitivity of the circuit nonidealities and decreases the internal signal swing to half the full scale. An implementation in a 0.35um CMOS technology achieved dynamic range of 88dB, bandwidth of 48 KHz and power consumption of 5mW. It can operate from supply voltages ranging from 2.4v–3.3v. The architecture is quite useful for low voltage SOC applications, such as portable biomedical system. (Abstract)