A novel variable inductor using a triple transformer and MOS switches in 0.13 μm CMOS technology

This paper presents a novel variable inductor consisting of a triple transformer, pMOSFET switches and a level shift circuit in 0.13 μm CMOS technology. The structure of the variable inductor is designed and analyzed by using Ansoft HFSS. The inductance varies from 0.678 nH to 1.055 nH with changing a control voltage from 0 to 1.5 V. The quality factor of the variable inductor is around 7 at 3.4 GHz.