Switched Inductor With Wide Tuning Range and Small Inductance Step Sizes

A switched inductor based on mutual-inductance switching is proposed that aims at increasing the inductance tuning range as well as the number of inductance step sizes. This is achieved with additional coupling structures and switch constellations. Applied to a 32 nm
LC
oscillator, the proposed inductor coil enables a frequency tuning range of 100% (1.5 octaves) from 2.8-8.4 GHz with switchable inductance values between 220 and 600 pH.