A second order hybrid continuous-discreet time sigma-delta modulator

Abstract

This paper describes a new second order hybrid sigma delta modulator where the discreet time filter is realized with fully differential current conveyor. The hybrid integrator, which is a combination of an analog integrator and a digital integrator, offers an increased dynamic range and helps make the resulting high-order sigma delta modulator stable. The convertor has been designed in a 0.18um TSMC technology and achieves a maximum signal to noise ratio 80dB in a 500KHz bandwidth and dissipates 23mW at 1.8V power supply.