Comparison of RF Inductor Performance Evaluation Methods

— Various model parameter calculation equations of RF CMOS inductors are compared. The calculation equations are using as variables either Y, Z-parameters or S-parameters. Results are based on on-wafer RF S-parameter measurements of a 3.75 turn spiral inductor fabricated in AMIS 0.7 μm CMOS DM1P n-well technology. Results obtained with calculation equations for a differentially driven inductor topology show differences evaluating the same model parameter, depending on whether Zand S-parameters are used. Thus, care must be taken by the designers when estimating an integrated inductor performance to comprehend the operating environment of the device and to choose the corresponding formulas accordingly. Key-words: RF CMOS inductors, model parameter evaluation, S-parameter measurements.