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

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 0.35 ¿m CMOS technology achieved dynamic range of 88 dB, bandwidth of 48 kHz and power consumption of 5 mW. It can operate from supply voltages ranging from 2.4 V-3.3 V. The architecture is quite useful for low voltage SOC applications, such as portable biomedical system.