Automatic Model Refinement Of Gmc Integrators For High-Level Simulation Of Continuous-Time Sigma-Delta Modulators

A Sigma Delta GmC integrator refinement flow is presented. The classically simplified GmC integrator small-signal model was upgraded to be extremely accurate by considering the complete transistor small-signal model. A circuit-level knowledge-based tool was used to execute the designer defined sizing procedure and to extract small signal parameters. By associating the symbolic transfer function to small-signal parameters, the flow, entirely implemented with C++, is able to compute poles and zeros to permit precise behavioral simulations. A 2(nd) order Sigma Delta modulator was chosen to visualize performance degradations while the specifications were not achievable.