A Magnetically Tuned Quadrature Oscillator

Continuous frequency tuning by control of the magnetic field of a transformer - capacitor tank, in a selective oscillator, is explored in this work. A quadrature generator is built connecting two identical transformer - capacitor oscillator cells in a feedback loop. The topology itself assures the currents in the transformer windings are aligned in phase, while their relative amplitude determines, via magnetic coupling, oscillators' tank reactance, i.e., oscillation frequency. This paper introduces the idea, analyzes oscillation amplitude, frequency tuning band, phase noise, and phase accuracy, and discusses design and experiments. Prototypes, realized in 65 nm CMOS, employing MOS varactors to further extend operation bandwidth, show the following performances: 3.2 GHz and 7.3 GHz minimum and maximum oscillation frequency, respectively. Phase noise figure of merit of 176.5 dB at 3.2 GHz and 170.5 dB at 6.4 GHz is observed, with 24 mW maximum power consumption and 1.5 maximum deviation from quadrature.

[1]  A. Rofougaran,et al.  A 900 MHz CMOS LC-oscillator with quadrature outputs , 1996, 1996 IEEE International Solid-State Circuits Conference. Digest of TEchnical Papers, ISSCC.

[2]  F. Svelto,et al.  On the amplitude and phase errors of quadrature LC-tank CMOS oscillators , 2006, IEEE Journal of Solid-State Circuits.

[3]  A. Fard,et al.  A study of phase noise in colpitts and LC-tank CMOS oscillators , 2005, IEEE Journal of Solid-State Circuits.

[4]  Salvatore Levantino,et al.  A low-phase-noise 5-GHz CMOS quadrature VCO using superharmonic coupling , 2003, IEEE J. Solid State Circuits.

[5]  Pietro Andreani,et al.  Analysis and Design of a 1.8-GHz CMOS LC , 2002 .

[6]  F. Svelto,et al.  Toward multistandard mobile terminals - fully integrated receivers requirements and architectures , 2005, IEEE Transactions on Microwave Theory and Techniques.

[7]  A. Bevilacqua,et al.  A 3.4-7 GHz Transformer-Based Dual-mode Wideband VCO , 2006, 2006 Proceedings of the 32nd European Solid-State Circuits Conference.

[8]  Minjae Lee,et al.  An 800-MHz–6-GHz Software-Defined Wireless Receiver in 90-nm CMOS , 2006, IEEE Journal of Solid-State Circuits.

[9]  Salvatore Levantino,et al.  Phase noise and accuracy in quadrature oscillators , 2004, 2004 IEEE International Symposium on Circuits and Systems (IEEE Cat. No.04CH37512).

[10]  Jean-Olivier Plouchart,et al.  Design of wide-band CMOS VCO for multiband wireless LAN applications , 2003, IEEE J. Solid State Circuits.

[11]  R. A. Hadaway,et al.  Monolithic transformers for silicon RF IC design , 1998, Proceedings of the 1998 Bipolar/BiCMOS Circuits and Technology Meeting (Cat. No.98CH36198).

[12]  A. Bonfanti,et al.  Analysis and design of a 1.8-GHz CMOS LC quadrature VCO , 2002, IEEE J. Solid State Circuits.

[13]  Mona M. Hella,et al.  Dual-band ultra-wide tuning range CMOS voltage-controlled oscillator , 2006 .

[14]  P. Andreani,et al.  A time-variant analysis of the 1/f/sup 2/ phase noise in CMOS parallel LC-tank quadrature oscillators , 2006, IEEE Transactions on Circuits and Systems I: Regular Papers.

[15]  A. Abidi,et al.  Physical processes of phase noise in differential LC oscillators , 2000, Proceedings of the IEEE 2000 Custom Integrated Circuits Conference (Cat. No.00CH37044).

[16]  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.

[17]  A.A. Abidi,et al.  A 3.1- to 8.2-GHz zero-IF receiver and direct frequency synthesizer in 0.18-/spl mu/m SiGe BiCMOS for mode-2 MB-OFDM UWB communication , 2005, IEEE Journal of Solid-State Circuits.

[18]  Carlo Samori,et al.  Spectrum folding and phase noise in LC tuned oscillators , 1998 .

[19]  Qiuting Huang.  Phase noise to carrier ratio in LC oscillators , 2000 .

[20]  A. Gnudi,et al.  A 0.83-2.5-GHz continuously tunable quadrature VCO , 2005, IEEE Journal of Solid-State Circuits.

[21]  P. Andreani,et al.  On the phase-noise and phase-error performances of multiphase LC CMOS VCOs , 2004, IEEE Journal of Solid-State Circuits.

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