UCLA

The models of CMOS RF inductors are reviewed and improved for design. A compact frequency-independent equivalent circuit is developed for symmetric inductors used in VCOs. The equivalent circuit captures three basic parasitic effects, current crowding, substrate loss, and distributed capacity. All values of LCRM originate from the inductor geometry with a minimum number of fitting parameters.

Simple optimizations are attempted for maximum Q at the operating frequency. Three representative inductors are analyzed using the equivalent circuit. Good agreements have been obtained between the measurement result and the model. The optimization processes prove the optimality of the three sample inductors.