Continuous Time Cascade Sigma Delta Modulator without digital cancellation filters

This work presents a design procedure for Continuous Time (CT) Cascade Sigma Delta Modulators (SDMs) using the Sturdy approach for Discrete Time Modulators, where the usual Digital Cancellation Filters are removed. The error cancellation mechanism is affected by excess loop delay in the CT approach. Special design considerations are derived and a specific design methodology is proposed. A 10-MHz bandwidth and 80-dB peak SNR example is designed and simulated using a 2-1 topology.