Analysis of the Sensibility of Switched-Capacitor Resonators at Base Band in Single-Bit High-Order ΣΔ Modulators

In order to improve both resolution and stability of single bit high order Sigma-Delta Modulators, quantization noise suppression should be carried out not only at DC but also within the bandwidth of interest. This noise suppression at frequencies different from zero is carried out with the use of resonators. Switched-Capacitor resonators at fS/n can be designed using integrating or delaying elements. In this work, both resonator structures are analyzed with respect to their robustness against the main imperfections presented in a SC implementation. The effect introduced by the operational transconductance amplifiers non-idealities was analyzed together with the effect of capacitor mismatch. Key-Words: Analog-digital Conversion, Switched Capacitor Circuits, Sigma-Delta modulation.