Passive Delta-Sigma ADC using multi-bit time-domain quantizer

Abstract

This paper proposes Passive Delta-Sigma modulator using multi-bit time domain quantizer. The number of portable devices operated by battery are increasing. So, it requires low power and high resolution. Delta-sigma modulator can achieve high resolution through oversampling and noise-shaping. But, it uses integrator used operational transconductance amplifier (OTA) which make consumes high power. To reduce power consumption, OTA must be eliminated from integrator. But with this, multi-bit quantizer is impractical because of signal attenuation in front of quantizer input. To resolve it, this paper uses time-domain quantizer to achieve multi-bit resolution. This ADC has been designed with 0.18 um CMOS process by magna, and simulation performed by Cadence Virtuoso Spectre circuit simulation and MATLAB.