Digital Compensated Methodology of a 2-1-1 cascaded continuous time delta-sigma modulator

Conventionally a continuous time (CT) cascaded delta-sigma modulator is designed by virtue of the transforming from its equivalent discrete time (DT) cascaded delta-sigma modulator with compensation paths in the analog part. This work presents a new approach that does not need analog compensation paths when implementing a high order cascaded CT delta-sigma modulator. We move the compensation paths to the digital cancellation filters, and it leads to a more efficient architecture in terms of circuitry complexity, power consumption, area cost, and the robustness of circuit non-ideality. A 2-1-1 CT cascaded delta-sigma modulator for audio band application was designed and simulated; the dynamic range is 83.7 dB. The simulation results indicate that the performance of this delta-sigma modulator is competitive to the conventional approach with less hardware complexity and power dissipation.