Abstract
Differential tuning in oscillators allows cancellation of common-mode bias noise and lower tuning sensitivity with respect to the most conventional single-ended tuning. However, the direct application of differential tuning increases the capacitor non-linearity and the flicker-induced phase noise. This paper analyzes quantitatively this phenomenon and proposes a novel configuration, which includes all the benefits of differential tuning with no penalty on phase noise. This circuit is fabricated in a 0.35-μm CMOS technology together with a single-end-tuned oscillator and both cover the 2.0–2.4 GHz frequency range. The measured 1/f3 phase noise at 10 kHz offset is −71 dBc/Hz, which outperforms the companion single-end tuning oscillator by 10 dB.
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A.L. Lacaita is also with IFN-CNR Sezione Milano.
Salvatore Levantino was born in 1973. He received the degree of Ingegnere in 1998 and the Ph.D. degree in electrical engineering in 2001 from the Politecnico di Milano, Italy. During his PhD program, he studied noise generation mechanisms in integrated oscillators and novel topologies for agile frequency synthesis. He also spent one year at Agere Systems (formerly Bell Laboratories), Murray Hill, NJ, working as consultant on IF-sampling receiver architectures. Since 2002, he is a post-doctoral researcher at the Politecnico di Milano. His research interests are mainly focused on fully integrated transceivers for wireless applications.
Andrea Bonfanti was born in Besana B.za (Milan), Italy, in 1972. He received the Laurea Degree and the Ph.D. in electronics engineering from the Politecnico di Milano, Italy, in 1999 and in 2002, respectively. Since 2003, he is a post-doctoral researcher at the Politecnico di Milano. His activity is focused on the design of frequency synthesizers for wireless applications in CMOS. His research interests also include ΔΣ analog-to-digital converters.
Luca Romanó was born in Milan, Italy, in 1976. He received the Laurea Degree in electronics engineering from the Politecnico di Milano, Milan, Italy, in 2001. He is currently working toward the Ph.D. degree in electronics and communications at the Politecnico di Milano. His research activity is oriented towards the development of frequency synthesizers for wireless broadband communications.
Carlo Samori was born in 1966, in Perugia, Italy. He received the Laurea Degree in electronics engineering in 1992, and the Ph.D. in electronics and communications at the Politecnico di Milano, Italy, in 1995. In 2002, he was appointed Associate Professor of Electronics at the Politecnico di Milano. He worked on solid-state photo-detector and the associated front-end electronics. His current research interests include design and analysis of integrated circuits for communications in bipolar and CMOS technologies, noise analysis in oscillators, frequency synthesizer architectures. Since 1997, he is a Consultant of the Wireless Communication Circuit Research Department of Agere Systems, Murray Hill.
Andrea L. Lacaita was born in 1962. He received the Laurea degree in nuclear engineering from the Politecnico di Milano, Italy, in 1985. In 1989–90, he was Visiting Scientist at the AT&T Bell Laboratories, Murray Hill, NJ, working on photo-refractive effects in superlattices for optical switching. In 1992, he became Associate Professor of Electronics at the Politecnico of Milano and since then, he has been teaching courses on electronics, electron devices, optoelectronics and solid-state physics. In 1999, he has been Academic Visitor at IBM T.J. Watson Research Center, Yorktown Heights, NY, where he contributed to the development of optical systems for IC testing. In 2000, he was appointed Full Professor of Electronics at the Politecnico di Milano and Head of the Microelectronics Lab. As researcher, he contributed to analog IC design with studies of phase noise in integrated LC-tuned oscillators and with the development of novel architectures of frequency synthesizers in RF front-ends. He has contributed to advances in microelectronics and optoelectronics, with particular emphasis on physics of single photon avalanche detectors, characterization and modeling of semiconductor devices. Within the field of ULSI microelectronics, he has studied carrier transport and quantum effect in scaled MOS transistors, technology and reliability of non-volatile memories. He is co-author of about 150 papers published in journals or presented in international conferences. He is also author of two books in Electronics.
Prof. Lacaita received in 1993 the Award of the Italian Association of Electrical and Electronic Engineers (AEI) for his research on hot carrier effects. In 1998–2000, he served as Coordinator of the Committee on micro-and nano-electron devices of the Italian National Group of Electronics Engineers. Since 2000, he has been consultant for the European Commission in the evaluation on review of research projects in micro- and nano-electronics. Since 2001, he has been serving in the program committee of the IEEE International Electron Device Meeting (IEDM) and he is now European Chair.
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Levantino, S., Bonfanti, A., Romanò, L. et al. Differentially-Tuned VCO with Reduced Tuning Sensitivity and Flicker Noise Up-Conversion. Analog Integr Circ Sig Process 42, 21–29 (2004). https://doi.org/10.1007/s10470-004-6844-0
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DOI: https://doi.org/10.1007/s10470-004-6844-0