Comparative study of gigahertz CMOS LC quadrature voltage-controlled oscillators with relevance to phase noise

Casha, Owen; Grech, Ivan; Micallef, Joseph

doi:10.1007/s10470-007-9090-4

Cited by 16 publications

(24 citation statements)

References 57 publications

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“…A Gilbert mixer cell was modified by adding resistors in series with the emitters in order to increase its dynamic range. Phase noise measurements of the quadrature LC-VCO are comparable to that obtained in literature for similar designs [8,12]. Phase errors from the phase shifter that are as large as 10 % would in most cases be unsuitable for a practical implementation.…”

Section: Resultssupporting

confidence: 72%

“…A frequency tuning range of 14 % was obtained and a maximum phase noise of −78.50 and −108.17 dBc/Hz was obtained at 100 kHz and 1 MHz offsets respectively. The quadrature VCO consumes 23.1 mW excluding its buffering circuitry and achieves a minimum VCO figure-of-merit (FOM) [12] of 157.81 dBc/Hz over the entire tuning range. Phase shift measurements were done using the Agilent E5071B RF Network Analyzer by forcing its input channels to scan across a 50 kHz bandwidth over the VCO carrier signal.…”

Section: Resultsmentioning

confidence: 99%

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A 4.3 GHz BiCMOS VCO with multiple 360° variable phase outputs using the vector sum method

Opperman

Sinha

2012

Analog Integr Circ Sig Process

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A 4.3 GHz voltage controlled oscillator (VCO) with multiple independently tunable phase outputs is presented. The VCO is realized by coupling two LC oscillators together in order to obtain quadrature signals and is tunable between 4.12 and 4.74 GHz. The variable phase outputs are achieved by varying the amplitudes of the in-phase and quadrature signals independently and then combining these signals together. By using multiple Gilbert cells as variable gain amplifiers (VGAs), multiple tunable phase outputs are achieved with the use of only one quadrature VCO. The VGAs are controlled using a custom non-linear digital-toanalog converter. The entire circuit is designed using a 3.3 V SiGe BiCMOS process. A maximum phase noise of −108.17 dBc/Hz was measured over the entire tuning range at a 1 MHz offset. The outputs of the VCO can be used as local oscillators that achieve phase shifting during radio frequency up or down conversion.

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Section: Resultssupporting

confidence: 72%

Section: Resultsmentioning

confidence: 99%

A 4.3 GHz BiCMOS VCO with multiple 360° variable phase outputs using the vector sum method

Opperman

Sinha

2012

Analog Integr Circ Sig Process

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“…To the authors' knowledge, this is the first reported superharmonic multiphase LC-VCO which thereby has the good attributes of the superharmonic coupling [3,10], and at the same time it is robust.…”

Section: Multiphase Signals Generationmentioning

confidence: 90%

New capacitive coupled superharmonic quadrature LC-VCO

Ebrahimi

Naseh

2010

IEICE Electron. Express

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Abstract:A study of some reported LC quadrature voltagecontrolled oscillators (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 crossconnected LC-VCOs is coupled via a capacitor to the node common between the two varactors in the LC tank of the other LC-VCO. 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 is no more than 1 o . 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.

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“…This was done to improve further the phase noise response obtained in [13]. In such QO-VCOs the phase relationship is not intrinsically deterministic as in a ring oscillator due to the bimodal oscillation effect, whereby the QO-VCO may exhibit two stable oscillation states at different operating frequencies [18]. A phase orientation circuit, shown in Fig.…”

Section: Quadrature Output Vcomentioning

confidence: 99%

“…The concept behind this circuit is that the coupling between the two VCOs is slightly reduced by injecting a small current in each tank which is in antiphase to the coupling current (e.g., the coupling current provided by M 7 is decreased by the current in M 15 since the latter is driven by a gate signal which is complementary to that of M 7 ), such that the VCOs are made to oscillate away from the state at which the bimodal oscillation effect occurs. Since this modification is carried out on both VCOs, their output signals remain in quadrature [18]. The QO-VCO is designed to operate at a centre frequency of 1.6 GHz with a tuning range of over 600 MHz.…”

Section: Quadrature Output Vcomentioning

confidence: 99%

CMOS implementation of a 1.6 GHz low voltage low phase noise quadrature output frequency synthesizer with automatic amplitude control

Casha

Grech

Micallef

et al. 2008

Analog Integr Circ Sig Process

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This article presents the design of a 1.2 V CMOS low phase noise quadrature output frequency synthesizer (FS) to be used for a GPS tuner application. Special reference is made to the design of a wide tuning range quadrature output voltage-controlled oscillator which is equipped with an automatic amplitude controller. It exhibits a phase noise response of less than -115 dBc/Hz at an offset of 1 MHz from the carrier and has a tuning range of over 36%. The effect of the automatic amplitude control is shown to improve phase noise at high oscillation frequencies and its noise has a negligible effect on the phase noise response even at low offset frequencies from the carrier. Preliminary analysis is presented showing the negligible effect of a DC-DC converter on the spurious level of the FS, included to permit the use of low sensitivity varactors. Design guidelines for reducing both the loop noise and the AM-to-PM conversion factors of the oscillator are also given. The design was made using the STMicroelectronics 0.13 lm HCMOS9-RF technology design kit.

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Comparative study of gigahertz CMOS LC quadrature voltage-controlled oscillators with relevance to phase noise

Cited by 16 publications

References 57 publications

A 4.3 GHz BiCMOS VCO with multiple 360° variable phase outputs using the vector sum method

A 4.3 GHz BiCMOS VCO with multiple 360° variable phase outputs using the vector sum method

New capacitive coupled superharmonic quadrature LC-VCO

CMOS implementation of a 1.6 GHz low voltage low phase noise quadrature output frequency synthesizer with automatic amplitude control

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