This paper demonstrates wide-band CMOS VCO based on the transformer feedback from traditional circuit to our proposed work. The start up condition of the traditional cross-coupled pair is expressed by the high frequency model. The wide band technique of this structure is derived with the help of the high frequency model of the transistor. Therefore, the wide band CMOS VCO based on the common source transformer feedback topology can achieves the high performance in the low voltage and low phase noise. The measurement result of the VCO exhibits the figure of merit, core power consumption and output power at supply voltage 0.8 V are –193.1 dBc/Hz, 4.4 mW and –2.3 dBm, respectively. The phase noise is –124.3 dBc/Hz at 1 MHz offset under the operation frequency 5.8 GHz. And the tuning range of the circuit can obtain 28%, this VCO is fabricated in TSMC 0.18μm 1P6MCMOS process.

A. Ravi, K. Soumyanath, R. E. Bishop, B. A. Bloechel and L. R. Carley, “An Optimally Transformer Coupled, 5 GHz Quadrature VCO in a 0.18 μm Digital CMOS Process,” Symposium on VLSI Circuits, Digest of Technical Papers, June 2003, pp. 141-144.

S. L. J. Gierkink, S. Levantino, R. C. Frye, C. Samori and V. Boccuzzi, “A Low-Phase-Noise 5-GHz CMOS Quadrature VCO Using Superharmonic Coupling,” IEEE Solid-State Circuits, Vol. 38, No. 7, 2003, pp. 1148-1154.
doi:10.1109/JSSC.2003.813297

D. Baek, T. Song, E. Yoon and S. Hong, “8-GHz CMOS Quadrature VCO Using Transformer-Based LC Tank,” IEEE Microwave and Wireless Components Letters, Vol. 13, No. 10, 2003, pp. 446-448.
doi:10.1109/LMWC.2003.815685

B. ?atl? and M. M. Hella, “A Dual Band, Wide Tuning Range CMOS Voltage Controlled Oscillator for MultiBand Radio,” IEEE Radio Frequency Integrated Circuits Symposium (RFIC), Honolulu, 3-5 June 2007, pp. 595598.

G. Cusmai, M. Repossi, G. Albasini, A. Mazzanti and F. Svelto, “A Magnetically Tuned Quadrature Oscillator,” IEEE Journal of Solid-State Circuits, Vol. 42, No. 12, 2007, pp. 2870-2877. doi:10.1109/JSSC.2007.908727

M. Demirkan, S. P. Bruss and R. R. Spencer, “Design of Wide Tuning-Range CMOS VCOs Using Switched Coupled-Inductors,” IEEE Journal of Solid-State Circuits, Vol. 43, No. 5, 2008, pp. 1156-1163.
doi:10.1109/JSSC.2008.920346

K. Kwok and H. C. Luong, “Ultra-Low-Voltage HighPerformance CMOS VCOs Using Transformer Feedback,” IEEE Solid-State Circuits, Vol. 40, No. 3, 2005, pp. 652-660. doi:10.1109/JSSC.2005.843614

C.-H. Chang and C.-Y. Yang, “A Low-Voltage High-Frequency CMOS LC-VCO Using a Transformer Feedback,” IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, 17 April-17 June 2008, pp. 545-548.

S.-L. Jang and C.-F. Lee, “A Low Voltage and Power LC VCO Implemented with Dynamic Threshold Voltage MOSFETS,” IEEE Microwave and Wireless Components Letters, Vol. 17, No. 5, 2007, pp. 376-378.
doi:10.1109/LMWC.2007.895720

M.-T. Hsu and H.-J. Li, “Design of High Performance and Wide-Band VCO with Transformer Feedback,” APMC Microwave Conference, Asia-Pacific, 16-20 December 2008, pp. 1-4.

M.-T. Hsu and Y.-H. Huang, “A Low Phase Noise and Low Power CMOS VCO with Transformer Feedback,” APMC Microwave Conference, Asia Pacific, 7-10 December 2009, pp. 2280-2283.

M.-T. Hsu, C.-T. Chiu and S.-H. Chen, “Low Power Design of CMOS 5-GHz Voltage-Controlled Oscillator from Narrowband to Wideband with Switching Capacitor Module,” IET Circuit Devices System, Vol. 3, No. 3, 2009, pp. 99-105. doi:10.1049/iet-cds.2008.0300

J. Yang, C.-Y. Kim, D.-W. Kim and S. Hong, “Design of a 24-GHz CMOS VCO with an Asymmetric-Width Transformer,” IEEE Transactions on Circuits and Systems—II: Express Briefs, Vol. 57, No. 3, 2010, pp. 173-177.

D. Ham and A. Hajimiri, “Concepts and Methods in Optimization of Integrated LC VCOs,” IEEE Journal of Solid-State Circuit, Vol. 36, No. 6, 2001, pp. 896-909.
doi:10.1109/4.924852

Y. Lee, S. Hyun and C. Kim, “Current Reuse Cross-Coupling CMOS VCO Using the Center-Tapped Transformer in LC Tank for Digitally Controlled Oscillator,” IEEE Radio Frequency Integrated Circuits (RFIC) Symposium, Atlanta, 17 April-17 June 2008, pp. 549-552.

C. H. Cao and K. O. Kenneth, “Millimeter-Wave VoltageControlled Oscillators in 0.13-μm CMOS Technology,” IEEE Solid-State Circuits, Vol. 41, No. 6, 2006, pp. 12971304.

J.-S. Syu, C. C. Meng and G.-W. Huang, “SiGe HBT Quadrature VCO Utilizing Trifilar Transformers,” IEEE Solid-State Circuits Conference, 3-5 November 2008, pp. 465-468.

A.-S. Porret, T. Melly, C. C. Enz and E. A. Vittoz, “Design of High-Q Varactors for Low-Power Wireless Applications Using a Standard CMOS Process,” IEEE Journal of Solid-State Circuits, Vol. 35, No. 3, 2000, pp. 337345. doi:10.1109/4.826815

A. W. L. Ng and H. C. Luong, “A 1-V 17-GHz 5-mW CMOS Quadrature VCO Based on Transformer Coupling,” IEEE Solid-State Circuits, Vol. 42, No. 9, 2007, pp. 1933-1941. doi:10.1109/JSSC.2007.903057

S.-J. Yun, N. D. B. Yen, I. Y. Lee, J.-T. Lee and S.-G. Lee, “A Differentially-Tuned Voltage Controlled Oscillator Using Symmetric Transformer,” IEEE Microwave and Wireless Components Letters, Vol. 18, No. 7, 2008, pp. 464-466. doi:10.1109/LMWC.2008.925108

Z. Safarian and H. Hashemi, “Wideband Multi-Mode CMOS VCO Design Using Coupled Inductors,” IEEE Transactions on Circuits and Systems I, Vol. 56, No. 8, 2009, pp. 1830-1843. doi:10.1109/TCSI.2009.2028414

J. M. Lopez-Villegas, J. Samitier, C. Cane, P. Losantos and J. Bausells, “Improvement of the Quality Factor of RF Integrated Inductors by Layout Optimization,” IEEE Transactions on Microwave Theory and Techniques, Vol. 48, No. 1, 2000, pp. 76-83. doi:10.1109/22.817474