Wide tuning range LC-oscillator in 65nm SOI CMOS, based on switchable secondary inductor

An LC-based VCO in standard 65 nm CMOS SOI technology is presented. The VCO exhibits a measured tuning range 6.4-11.3 GHz. The tuning range is significantly extended by a combination of switchable inductor and capacitor banks. The switchable inductor consists of two magnetically coupled spiral inductors. The secondary coil can be either open or closed with a large FET switch, which in closed condition significantly reduces the inductance of the main coil by means of mutual inductance.

[1]  A.M. Niknejad,et al.  A 1.8-GHz LC VCO with 1.3-GHz tuning range and digital amplitude calibration , 2005, IEEE Journal of Solid-State Circuits.

[2]  F. Ellinger,et al.  60 GHz VCO with wideband tuning range fabricated on VLSI SOI CMOS technology , 2004, 2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535).