A 3.9–4.5GHz class-C VCO with accurate current injection based on capacitive feedback

A class-C VCO with dual negative feedback architecture is proposed to break the trade-off between amplitude stability of oscillation and bias current flicker noise. Inherent dynamic biasing of this architecture maximizes available voltage swing and provides robust current control without any additional circuits. To inject current exactly at the peak of oscillation, a capacitive feedback technique is proposed which improves phase noise performance further by compensating current injection delay caused due to cross-coupled pair parasitics. This VCO has been implemented in 130nm BiCMOS technology using BJT based cross-coupled pair. It exhibits phase noise performance of −131dBc/Hz @ 1MHz offset when running at 3.9GHz. It exhibits a 14% tuning range, and presents an FoM of 184dBc/Hz.

[1]  Kenichi Okada,et al.  A pulse-driven LC-VCO with a figure-of-merit of −192dBc/Hz , 2014, ESSCIRC 2014 - 40th European Solid State Circuits Conference (ESSCIRC).

[2]  Wouter A. Serdijn,et al.  Spectral Analysis of Phase Noise in Bipolar LC-Oscillators—Theory, Verification, and Design , 2010, IEEE Transactions on Circuits and Systems I: Regular Papers.

[3]  A. Mazzanti,et al.  Class-C Harmonic CMOS VCOs, With a General Result on Phase Noise , 2008, IEEE Journal of Solid-State Circuits.

[4]  K. Okada,et al.  A constant-current-controlled class-C VCO using a self-adjusting replica biasing scheme , 2013, 2013 European Microwave Integrated Circuit Conference.

[5]  Yintang Yang,et al.  A Startup Robust Feedback Class-C VCO With Constant Amplitude Control in 0.18 $\mu$m CMOS , 2015, IEEE Microwave and Wireless Components Letters.

[6]  Kenichi Okada,et al.  Class-C VCO With Amplitude Feedback Loop for Robust Start-Up and Enhanced Oscillation Swing , 2013, IEEE Journal of Solid-State Circuits.

[7]  Pietro Andreani,et al.  A 6.7-to-9.2GHz 55nm CMOS hybrid Class-B/Class-C cellular TX VCO , 2012, 2012 IEEE International Solid-State Circuits Conference.

[8]  Massoud Tohidian,et al.  High-swing class-C VCO , 2011, 2011 Proceedings of the ESSCIRC (ESSCIRC).

[9]  Pietro Andreani,et al.  Low-phase-noise 3.4–4.5 GHz dynamic-bias class-C CMOS VCOs with a FoM of 191 dBc/Hz , 2012, 2012 Proceedings of the ESSCIRC (ESSCIRC).

[10]  Pietro Andreani,et al.  An Analysis of Phase Noise in Bipolar Colpitts Oscillators (With a Digression on Bipolar , 2007 .

[11]  Ali Hajimiri,et al.  A general theory of phase noise in electrical oscillators , 1998 .

[12]  Fabrizio Palma,et al.  A robust start-up Class-C CMOS VCO based on a common mode low frequency feedback loop , 2014, ESSCIRC 2014 - 40th European Solid State Circuits Conference (ESSCIRC).