An Active Inductor-Based VCO With Wide Tuning Range and High DC-to-RF Power Efficiency

An active inductor-based voltage-controlled oscillator (VCO) with a wide frequency tuning range was designed and fabricated using a standard 0.13-μm CMOS process. The oscillator has an LC-tank topology with cross-coupled transistors, and the active inductor was realized using a pair of fully differential very high-speed operational transconductance amplifiers. Due to the differential nature of the inductor, the even harmonics of the output signal were much reduced. Measured results show that the VCO is tunable from 833 MHz to 3.72 GHz, representing a tuning range of 127%. The VCO can produce -0.9 dBm of radio-frequency power. The core circuit, excluding output buffers, consumes 13 mW from a 1.2-V supply.

[1]  Liang-Hung Lu,et al.  A Wide Tuning-Range CMOS VCO With a Differential Tunable Active Inductor , 2006, IEEE Transactions on Microwave Theory and Techniques.

[2]  Carlos E. Saavedra,et al.  Feedforward-Regulated Cascode OTA for Gigahertz Applications , 2008, IEEE Transactions on Circuits and Systems I: Regular Papers.

[3]  Fei Yuan.  CMOS Active Inductors and Transformers: Principle, Implementation, and Applications , 2008 .

[4]  F. Yuan.  CMOS Active Inductors , 2008 .

[5]  C.-J. Richard Shi,et al.  A 6–11GHz multi-phase VCO design with active inductors , 2008, 2008 IEEE International Symposium on Circuits and Systems.

[6]  Jae W. Lee,et al.  High quality-factor and inductance of symmetric differential-pair structure active inductor using a feedback resistance design , 2008, 2008 IEEE MTT-S International Microwave Symposium Digest.

[7]  Chin-Wei Kuo,et al.  Improved quality-factor of 0.18-/spl mu/m CMOS active inductor by a feedback resistance design , 2002 .

[8]  P. Sen,et al.  Reconfigurable RFICs in Si-based technologies for a compact intelligent RF front-end , 2005, IEEE Transactions on Microwave Theory and Techniques.

[9]  Carlos E. Saavedra,et al.  Full 360$^{\circ }$ Vector-Sum Phase-Shifter for Microwave System Applications , 2010, IEEE Transactions on Circuits and Systems I: Regular Papers.

[10]  Carlos E. Saavedra,et al.  Wideband microwave OTA with tunable transconductance using feedforward regulation and an active inductor load , 2010, Proceedings of the 8th IEEE International NEWCAS Conference 2010.

[11]  Mohammed Ismail,et al.  CMOS VHF/RF CCO based on active inductors , 2001 .

[12]  J. Laskar,et al.  Active Inductor-Based Oscillator: A Promising Candidate for Low-Cost Low-Power Multi-Standard Signal Generation , 2007, 2007 IEEE Radio and Wireless Symposium.