Design of a continuous-time current-mode sigma-delta analog-to-digital converter

Abstract

The importance of the Analog-to-Digital converters (ADC) is increasing due to the necessity of an interface between the analog and digital world where computing and signal processing are executed. Over the last years, their low cost development and good linearity made sigma-delta (ΣΔ) type converters widely available. In this thesis, due to their various advantages like low voltage operation, and lower power consumption than their discrete time (DT) counterpart, continuous time (CT) ΣΔ has been studied. This thesis presents the design of a continuous time current-mode ΣΔ ADC starting from the building blocks as integrator, comparator and digital to analog converter (DAC) and its control circuitry. The transistor level circuit designs are verified with SPICE simulations.