MOS varactors with n- and p-type gates and their influence on an LC-VCO in digital CMOS

Maget, J.; Tiebout, M.; Kraus, R.

doi:10.1109/jssc.2003.813288

Cited by 47 publications

(13 citation statements)

References 37 publications

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“…It is conjectured that, for 3 / 1 m f region, the variation of capacitance of varactor's C-V behavior plays an important role. [8] In the I-mode the lowest phase noise happens as V tune is larger than 2V, in which all the swing falls in the depletion region with nearly fixed capacitance. The up-conversion effect of flicker noise is reduced.…”

Section: A-mode Varactormentioning

confidence: 98%

Study of phase noise in VCXO with inversion-mode varactors

Kao

Liau

2013

2013 Joint European Frequency and Time Forum &Amp; International Frequency Control Symposium (EFTF/IFC)

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Voltage controlled crystal oscillators (VCXO) using CMOS varactors are investigated. The varactor is operated in the so-called inversion mode (I-Mode) with source and drain bounded together. Its capacitance is evaluated by the HSPICSFourier methodology. The performances of capacitance under small-signal and large-signal operations are classified. Then the frequency tuning and the related phase noise are explored. It is found that the larger the tuning coefficient has, the worse the phase noise has in I-mode varactor. The chip is fabricated by the TSMC 0.35um CMOS process. The total area including pad is 1.358 1.350 mm 2 and the current consumption in the core circuit is 300uA.

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Section: A-mode Varactormentioning

confidence: 98%

Study of phase noise in VCXO with inversion-mode varactors

Kao

Liau

2013

2013 Joint European Frequency and Time Forum &Amp; International Frequency Control Symposium (EFTF/IFC)

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“…The methods of reducing the nonlinearity of the varactor includes, combining a discrete digital-switching capacitor bank and MOS varactor for coarse and fine frequency tuning, which requires additional calibration time [2]; connecting a varactor bank with different bias voltage in parallel to get an equalized K VCO , which needs an additional bias circuit [3,4,5]; adopting a new varactor device with the n-type and p-type mixed-doping gates with a special process [6,7]. In this paper, a simple but efficient gain linearized varactor is proposed, consisting of the gate-bulk capacitance (C GB ) of an AMOS and PMOS.…”

Section: Introductionmentioning

confidence: 99%

A linearized tuning varactor for voltage controlled oscillator

Xia

et al. 2017

IEICE Electron. Express

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A linearized tuning varactor for the voltage controlled oscillator (VCO) is proposed in this paper. The capacitance-voltage (C-V) curve is linearized by combining an accumulation MOSFET (AMOS) and PMOS in parallel to form the varactor. Two ring voltage controlled oscillators (ring VCOs) are fabricated and measured with a standard 65-nm CMOS process. They are both identical except for the varactor. The first VCO uses the proposed varactor, and the second one is tuned by a conventional AMOSonly varactor for reference. The ring VCO with the proposed varactor operates from 500.5 to 807.6 MHz, and the VCO gain (K VCO ) varies from 183 to 284 MHz/V. Comparing the reference VCO with the AMOS-only varactor, the measured K VCO variability is reduced by 82%. The phase noise is between −89 dBc/Hz and −92 dBc/Hz at 1 MHz offset while dissipating 0.8 mA from a 1.2-V supply.

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“…The Q of the tank will determine the VCO's phase noise and power consumption (Maget et al 2003). Therefore, they will be dominated by the Q of the inductor for low frequency range, and the Q of the varactor at higher range, such as mm-wave.…”

Section: Introductionmentioning

confidence: 99%