A Distributed Dual-Band LC Oscillator Based on Mode Switching

Li, Guansheng; Afshari, Ehsan

doi:10.1109/tmtt.2010.2091203

Cited by 56 publications

(37 citation statements)

References 22 publications

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“…6(b). It is straightforward to prove this result by applying impulse sensitivity function (ISF) method [3] in the same way as in [10]. For the sake of space, we will verify this result by simulation instead of lengthy mathematical derivation in Section III-C.…”

Section: A Comparison With Conventional Lc Vcosmentioning

confidence: 85%

“…This has been demonstrated as an alternative way of trading power for phase noise, which avoids scaling inductance down to impractically small values in scaled CMOS process. For instance, 4-coupled oscillators [1], [11] and a 2-coupled one [10] were demonstrated to achieve 6 dB and 3 dB phase noise reduction at the cost of 6 dB and 3 dB more power, respectively.…”

Section: A Comparison With Conventional Lc Vcosmentioning

confidence: 99%

“…Thus, it doubles the frequency tuning range without degrading phase noise performance, which eases the tradeoff between phase noise and tuning range. Secondly, the proposeddesigncanbe consideredas twoidenticalLC VCOscoupled together and thus can bring phase noise down by 3 dB to meet specifications without scaling to impractically small values [10]. Finally, the effective inductance of the proposed resonator is larger in its low-frequency band and smaller in its high-frequency band.…”

Section: Introductionmentioning

confidence: 99%

“…However, the impedance and quality factor of the resonator change significantly from mode to mode, which leads to inferior phase noise performance in one or more of the bands. A capacitive coupling method was also proposed, in which two identical LC tanks are coupled by capacitors to generate two resonant frequencies and reduce phase noise [10]. However, the two inductors takes a large area; and the coupling capacitor loads the resonator as fixed capacitor in one of the modes and limits the frequency tuning range in that mode.…”

Section: Introductionmentioning

confidence: 99%

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A Low-Phase-Noise Wide-Tuning-Range Oscillator Based on Resonant Mode Switching

Liu

Tang

et al. 2012

IEEE J. Solid-State Circuits

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150

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In this paper we will present a low-phase-noise wide-tuning-range oscillator suitable for scaled CMOS processes. It switches between the two resonant modes of a high-order LC resonator that consists of two identical LC tanks coupled by capacitor and transformer. The mode switching method does not add lossy switches to the resonator and thus doubles frequency tuning range without degrading phase noise performance. Moreover, the coupled resonator leads to 3 dB lower phase noise than a single LC tank, which provides a way of achieving low phase noise in scaled CMOS process. Finally, the novel way of using inductive and capacitive coupling jointly decouples frequency separation and tank impedances of the two resonant modes, and makes it possible to achieve balanced performance. The proposed structure is verified by a prototype in a low power 65 nm CMOS process, which covers all cellular bands with a continuous tuning range of 2.5-5.6 GHz and meets all stringent phase noise specifications of cellular standards. It uses a 0.6 V power supply and achieves excellent phase noise figure-of-merit (FoM) of 192.5 dB at 3.7 GHz and 188 dB across the entire tuning range. This demonstrates the possibility of achieving low phase noise and wide tuning range at the same time in scaled CMOS processes.Index Terms-Coupled oscillator, dual band, low phase noise, mode switching, VCO, wide tuning range oscillator.

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Section: A Comparison With Conventional Lc Vcosmentioning

confidence: 85%

Section: A Comparison With Conventional Lc Vcosmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Low-Phase-Noise Wide-Tuning-Range Oscillator Based on Resonant Mode Switching

Liu

Tang

et al. 2012

IEEE J. Solid-State Circuits

Self Cite

150

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“…The dimensionless factors and are calculated by the following formula (11) taking the minus sign and the plus sign, respectively. In a similar manner it is possible to determine the amplitude of the oscillation corresponding to (7), which will be shown to be unstable in the next section.…”

Section: B Amplitudes Of Oscillationmentioning

confidence: 99%

Analysis and Design of Dual-Mode CMOS LC-VCOs

Buonomo¹,

Schiavo²

2015

IEEE Trans. Circuits Syst. I

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We present a nonlinear analysis of the basic circuit of a dual-band voltage controlled oscillator (VCO), composed by an active one-port and by a double-tuned LC circuit. Both the frequencies and the amplitudes of the two modes of sinusoidal oscillation are calculated by closed-form expressions by which a detailed analysis of the steady-state and dynamical behavior of circuit is performed, including the stability analysis of the modes. We show the appearance of the phenomenon of the frequency hysteresis allowing us to explain the mechanism of the switching between modes and predict the VCOs performance over the whole operation range. The theoretical results, validated by Spice simulations of a VCO realized in 0.13 m MOS technology and by measurements on a circuit prototype, provide useful design insights.Index Terms-Analog integrated circuits, dual-band voltagecontrolled oscillators (VCO), microwave oscillators, multiband VCOs, nonlinear systems. 1549-8328

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