Scalable compact circuit model and synthesis for RF CMOS spiral inductors

A scalable industry-oriented, 24-element "2-π" compact circuit model for on-chip RF CMOS spiral inductors is presented. It has a good accuracy up to self-resonant frequency (SRF). Two levels of modeling approaches are provided, which are: 1) the fixed model, which extracts the values of circuit elements directly from the measured S-parameters of a given device, achieving high accuracy, but no scalability and 2) the scalable model, in which circuit elements are related to the geometry (i.e., layout) through a set of formulas with model parameters calibrated upon a few testing devices. The synthesis procedure is also discussed, which includes the scalable model and a SPICE simulator as the evaluation method within the iteration loop.