High-Q MOS Varactor Models for Quasi-Millimeter-Wave Low-Noise LC-VCOs

Yuka ITANO; Shotaro MORIMOTO; Sadayuki YOSHITOMI; Nobuyuki ITOH

doi:10.1587/transfun.E97.A.759

High-Q MOS Varactor Models for Quasi-Millimeter-Wave Low-Noise LC-VCOs

Yuka ITANO, Shotaro MORIMOTO, Sadayuki YOSHITOMI, Nobuyuki ITOH

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This paper presents the strategy of MOS varactor's high-Q optimization, a novel scalable model for the quasi-millimeter-wave MOS varactors, and confirmation results by discrete MOS varactors and VCO measurements. To realize a high-Q MOS varactor in the quasi-millimeter-wave region, low MOS varactor capacitance and low series resistance of unit cell are essential. Downsizing is a key to realize both low capacitance and low resistance. However, it is induced by C_max/C_min reduction, simultaneously. Therefore, scalable MOS varactor model is necessary to use optimum MOS varactor to cover various application requirements using same process. Decreasing the MOS varactor's size of W/L =2µm/2µm to 0.5µm/0.26µm, the Q factor increased sevenfold at f =20GHz but C_max/C_min is reduced by 60%, by using conventional PSP model, an error of approximately 20% is shown. Proposed model has been improved its accuracy from 18.9% to 0.2% for N⁺ MOS varactor and from 22.1% to 0.8% for P⁺ MOS varactor, for minimum size of MOS varactor even if model covers wide dimension range. Also, it has been confirmed this model is covered in two types of layouts. Oscillation frequency and phase noise also have been confirmed by three types of 22GHz VCOs. The accuracy of oscillation frequency is less than 2.5% and that of phase noise at 1MHz offset from carrier is less than 5dB.

Publication: IEICE TRANSACTIONS on Fundamentals Vol.E97-A No.3 pp.759-767

Publication Date: 2014/03/01

Publicized

Online ISSN: 1745-1337

DOI: 10.1587/transfun.E97.A.759

Type of Manuscript: Special Section PAPER (Special Section on Analog Circuit Techniques and Related Topics)

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Authors

Yuka ITANO
  Okayama Prefectural University,TOSHIBA
Shotaro MORIMOTO
  Okayama Prefectural University
Sadayuki YOSHITOMI
  TOSHIBA
Nobuyuki ITOH
  Okayama Prefectural University

Keyword

MOS varactor, quasi-millimeter wave, modeling, LC-VCO

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Yuka ITANO, Shotaro MORIMOTO, Sadayuki YOSHITOMI, Nobuyuki ITOH, "High-Q MOS Varactor Models for Quasi-Millimeter-Wave Low-Noise LC-VCOs" in IEICE TRANSACTIONS on Fundamentals, vol. E97-A, no. 3, pp. 759-767, March 2014, doi: 10.1587/transfun.E97.A.759.
Abstract: This paper presents the strategy of MOS varactor's high-Q optimization, a novel scalable model for the quasi-millimeter-wave MOS varactors, and confirmation results by discrete MOS varactors and VCO measurements. To realize a high-Q MOS varactor in the quasi-millimeter-wave region, low MOS varactor capacitance and low series resistance of unit cell are essential. Downsizing is a key to realize both low capacitance and low resistance. However, it is induced by C_max/C_min reduction, simultaneously. Therefore, scalable MOS varactor model is necessary to use optimum MOS varactor to cover various application requirements using same process. Decreasing the MOS varactor's size of W/L =2µm/2µm to 0.5µm/0.26µm, the Q factor increased sevenfold at f =20GHz but C_max/C_min is reduced by 60%, by using conventional PSP model, an error of approximately 20% is shown. Proposed model has been improved its accuracy from 18.9% to 0.2% for N⁺ MOS varactor and from 22.1% to 0.8% for P⁺ MOS varactor, for minimum size of MOS varactor even if model covers wide dimension range. Also, it has been confirmed this model is covered in two types of layouts. Oscillation frequency and phase noise also have been confirmed by three types of 22GHz VCOs. The accuracy of oscillation frequency is less than 2.5% and that of phase noise at 1MHz offset from carrier is less than 5dB.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1587/transfun.E97.A.759/_p

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@ARTICLE{e97-a_3_759,
author={Yuka ITANO, Shotaro MORIMOTO, Sadayuki YOSHITOMI, Nobuyuki ITOH, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={High-Q MOS Varactor Models for Quasi-Millimeter-Wave Low-Noise LC-VCOs},
year={2014},
volume={E97-A},
number={3},
pages={759-767},
abstract={This paper presents the strategy of MOS varactor's high-Q optimization, a novel scalable model for the quasi-millimeter-wave MOS varactors, and confirmation results by discrete MOS varactors and VCO measurements. To realize a high-Q MOS varactor in the quasi-millimeter-wave region, low MOS varactor capacitance and low series resistance of unit cell are essential. Downsizing is a key to realize both low capacitance and low resistance. However, it is induced by C_max/C_min reduction, simultaneously. Therefore, scalable MOS varactor model is necessary to use optimum MOS varactor to cover various application requirements using same process. Decreasing the MOS varactor's size of W/L =2µm/2µm to 0.5µm/0.26µm, the Q factor increased sevenfold at f =20GHz but C_max/C_min is reduced by 60%, by using conventional PSP model, an error of approximately 20% is shown. Proposed model has been improved its accuracy from 18.9% to 0.2% for N⁺ MOS varactor and from 22.1% to 0.8% for P⁺ MOS varactor, for minimum size of MOS varactor even if model covers wide dimension range. Also, it has been confirmed this model is covered in two types of layouts. Oscillation frequency and phase noise also have been confirmed by three types of 22GHz VCOs. The accuracy of oscillation frequency is less than 2.5% and that of phase noise at 1MHz offset from carrier is less than 5dB.},
keywords={},
doi={10.1587/transfun.E97.A.759},
ISSN={1745-1337},
month={March},}

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TY - JOUR
TI - High-Q MOS Varactor Models for Quasi-Millimeter-Wave Low-Noise LC-VCOs
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 759
EP - 767
AU - Yuka ITANO
AU - Shotaro MORIMOTO
AU - Sadayuki YOSHITOMI
AU - Nobuyuki ITOH
PY - 2014
DO - 10.1587/transfun.E97.A.759
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E97-A
IS - 3
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - March 2014
AB - This paper presents the strategy of MOS varactor's high-Q optimization, a novel scalable model for the quasi-millimeter-wave MOS varactors, and confirmation results by discrete MOS varactors and VCO measurements. To realize a high-Q MOS varactor in the quasi-millimeter-wave region, low MOS varactor capacitance and low series resistance of unit cell are essential. Downsizing is a key to realize both low capacitance and low resistance. However, it is induced by C_max/C_min reduction, simultaneously. Therefore, scalable MOS varactor model is necessary to use optimum MOS varactor to cover various application requirements using same process. Decreasing the MOS varactor's size of W/L =2µm/2µm to 0.5µm/0.26µm, the Q factor increased sevenfold at f =20GHz but C_max/C_min is reduced by 60%, by using conventional PSP model, an error of approximately 20% is shown. Proposed model has been improved its accuracy from 18.9% to 0.2% for N⁺ MOS varactor and from 22.1% to 0.8% for P⁺ MOS varactor, for minimum size of MOS varactor even if model covers wide dimension range. Also, it has been confirmed this model is covered in two types of layouts. Oscillation frequency and phase noise also have been confirmed by three types of 22GHz VCOs. The accuracy of oscillation frequency is less than 2.5% and that of phase noise at 1MHz offset from carrier is less than 5dB.
ER -