Dynamic range scaling of sigma-delta modulators based on a multi-criteria optimization process

Abstract

This paper presents a new coefficient scaling technique to determine the dynamic range of the integrators of sigma delta modulators. This technique relies on numerical optimization of the interstage coefficients to minimize a multi-criteria objective function taking into account the sum of capacitor values implementing the modulator and the voltage swing at each integrator output, for a given target SNR. The optimization process includes the effect of thermal noise at each integrator stage. A user-defined parameter can steer the optimization process priority towards either the size of the capacitors or the integrators output voltage swing, depending on the given application.