Analysis of on-chip spiral inductors using the distributed capacitance model

A distributed capacitance model (DCM) for monolithic spiral inductors is developed to predict the equivalent coupling capacitances Cpbetween the two terminals and the equivalent capacitance between the metal track and the substrate C/sub sub/. Therefore, the characteristics of inductors such as the S parameter, the quality factor Q, and the self-resonant frequency f/sub SR/ can be predicted by its series inductance, equivalent capacitances, and series resistance. A large number of inductors have been implemented in 0.25- and 0.35-μm CMOS processes to demonstrate the prediction accuracy. For planar and multilayer inductors, DCM can provide a quick and accurate assessment to the design of monolithic spiral inductors.