A new robust capacitively coupled second harmonic quadrature LC oscillator
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A study of some reported superharmonic LC quadrature voltage-controlled oscillator (LC-QVCO) is performed in which it is shown that robustness of the quadrature oscillation varies depending on the coupling configuration. Next, a new superharmonic LC-QVCO is proposed in which the common source node in either of two identical cross-connected LC-VCOs is coupled via a capacitor to the node common between the two varactors in the LC-tank of the other LC-VCO. As a result of connecting common mode nodes, the currents flowing through the two coupling capacitors are comprised of only the even harmonics. In the proposed coupling configuration there exists a closed loop through which the second harmonic signals circulate. A qualitative argument is presented to justify the robustness of the quadrature nature of the proposed QVCO by applying the Barkhausen phase criterion to the second harmonic signals in the loop. Since the coupling devices are only two capacitors, no extra noise sources and power consumption are added to the core VCOs. A Monte-Carlo simulation showed that the phase error of the proposed QVCO caused by device mismatches is no more than 1°. Also, generalizing this method to several numbers of VCOs in a loop, multiphase signals can be generated. The proposed circuits were designed using a 0.18-μm RF CMOS technology and simulation results are presented.
- Razavi, B. (1998). RF microelectronics. Upper Saddle River, NJ: Prentice Hall.
- Rofougaran, A., et al. (1998). A single-chip 900-MHz spread-spectrum wireless transceiver in 1-μm CMOS-Part I: Architecture and transmitted design. IEEE Journal of Solid-State Circuits, 33, 515–534. CrossRef
- Andreani, A., Bonfanti, A., Romano, L., & Samori, C. (2002). Analysis and design of 1.8 GHz CMOS LC quadrature oscillator. IEEE Journal of Solid-State Circuits, 37(12), 1737–1747. CrossRef
- Ebrahimi, E., & Naseh, S. (2009). A CMOS low-noise low-power quadrature LC oscillator. In IEEE International Symposium on Circuits and Systems, pp. 1305–1308.
- Tortori, P., et al. (2009). Quadrature VCOs based on direct second harmonic locking: Theoretical analysis and experimental validation. International Journal of Circuit Theory and Applications. doi:10.1002/cta.612.
- Gierkink, S., Levantino, S., Frye, R., Samori, C., & Boccuzzi, V. (2003). A low-phase-noise 5-GHz CMOS quadrature VCO using superharmonic coupling. IEEE Journal of Solid-State Circuits, 38(7), 1148–1154. CrossRef
- Hancock, T. M., & Rebeiz, G. (2004). A novel superharmonic coupling topology for quadrature oscillator design at 6 GHz. In IEEE Radio Frequency Integrated Circuits Symposium, pp. 285–288.
- Soltanian, B., & Kinget, P. (2006). A low phase noise quadrature LC VCO using capacitive common-source coupling. In European Solid-State Circuits Conference, pp. 436–439.
- Naseh, S., Zarre, M., & Jamal Deen, M. (2008). A low-voltage low-noise superharmonic quadrature oscillator. In IEEE International Conference on Electronics, Circuits and Systems, pp. 400–403.
- Tortori, P., Guermandi, D., Franchi, E., & Gnudi, A. (2004). Quadrature VCO based on direct second harmonic locking. In IEEE International Symposium on Circuits and Systems, pp. I-169–I-172.
- Tiebout, M. (2001). Low-power low-phase-noise differentially tuned quadrature VCO design in standard CMOS. IEEE Journal of Solid-State Circuits, 36, 1018–1024. CrossRef
- Alan, W. L., & Luong, H. C. (2006). A 1 V 17 GHz 5mW quadrature CMOS VCO based on transformer coupling. In IEEE International Solid-State Circuits Conference, pp. 711–720.
- Cabanillas, J., Dussopt, L., Lopez-Villegas, J. M., & Rebeiz, G. M. (2002). A 900 MHz low phase noise CMOS quadrature oscillator. In IEEE Radio Frequency Integrated Circuits Symposium, pp. 63–66.
- Jackson, B. R., & Saavedra, C. E. (2007). A 3 GHz CMOS quadrature oscillator using active superharmonic coupling. In Proceedings of the 37th European Microwave Conference, pp. 1109–1112.
- Casha, O., Grech, I., & Micallef, J. (2007). Comparative study of gigahertz CMOS LC quadrature voltage-controlled oscillators with relevance to phase noise. Analog Integrated Circuits and Signal Processing, 52, 1–14. CrossRef
- Romano, L., et al. (2004). Phase noise and accuracy in quadrature oscillators. In IEEE International Symposium on Circuits and Systems, pp. I-161–I-164.
- Ohira, T., & Araki, K. (2007). Active Q-factor and equilibrium stability formulation for sinusoidal oscillators. IEEE Transactions on Circuits and Systems Part II, 54(9), 810–814. CrossRef
- Palumbo, G., Pennisi, M., & Pennisi, S. (2009). Approach to analyse and design nearly sinusodial oscillators. IET Circuits Devices and Systems, 3(4), 204–221. CrossRef
- A new robust capacitively coupled second harmonic quadrature LC oscillator
Analog Integrated Circuits and Signal Processing
Volume 66, Issue 2 , pp 269-275
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- LC quadrature voltage-controlled oscillators
- Low-phase noise
- Quadrature robustness
- Superharmonic QVCO
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