Large-Signal Analysis of MOS Varactors

connected, inversion-mode (I-MOS), and accumulation-mode (A-MOS) structures. When incorporated into the VCO tank circuit, the large-signal swing of the VCO output oscillation modulates the varactor capacitance in time, resulting in a VCO tuning curve that deviates from the dc tuning curve of the particular varactor structure. This paper presents a detailed analysis of this large-signal effect. Simulated results are compared to measurements for an example 2.5-GHz complementary LC VCO using I-MOS varactors implemented in 0.35- m CMOS technology.

[1]  Leon O. Chua,et al.  Introduction to nonlinear network theory , 1969 .

[2]  T.H. Lee.  CMOS RF: no longer an oxymoron , 1997, GaAs IC Symposium. IEEE Gallium Arsenide Integrated Circuit Symposium. 19th Annual Technical Digest 1997.

[3]  Chih-Ming Hung,et al.  High-Q capacitors implemented in a CMOS process for low-power wireless applications , 1998 .

[4]  Salvatore Levantino,et al.  Frequency dependence on bias current in 5 GHz CMOS VCOs: impact on tuning range and flicker noise upconversion , 2002, IEEE J. Solid State Circuits.

[5]  G. Li Puma,et al.  A 2-GHz low-phase-noise integrated LC-VCO set with flicker-noise upconversion minimization , 2000, IEEE Journal of Solid-State Circuits.

[6]  B. Razavi,et al.  A 1.8 GHz CMOS voltage-controlled oscillator , 1997, 1997 IEEE International Solids-State Circuits Conference. Digest of Technical Papers.

[7]  P. Andreani,et al.  On the use of MOS varactors in RF VCOs , 2000, IEEE Journal of Solid-State Circuits.

[8]  P. Andreani,et al.  A comparison between two 1.8GHz CMOS VCOs tuned by different varactors , 1998, Proceedings of the 24th European Solid-State Circuits Conference.

[9]  Ali Hajimiri,et al.  Concepts and methods in optimization of integrated LC VCOs , 2001, IEEE J. Solid State Circuits.

[10]  S. Simon Wong,et al.  Analysis and optimization of accumulation-mode varactor for RF ICs , 1998, 1998 Symposium on VLSI Circuits. Digest of Technical Papers (Cat. No.98CH36215).

[11]  P. Allen,et al.  Low-power, low-phase-noise CMOS voltage-controlled-oscillator with integrated LC resonator , 1998, ISCAS '98. Proceedings of the 1998 IEEE International Symposium on Circuits and Systems (Cat. No.98CH36187).

[12]  R. Castello,et al.  A 1.3 GHz low-phase noise fully tunable CMOS LC VCO , 2000, IEEE Journal of Solid-State Circuits.

[13]  M. Tiebout,et al.  Low-power low-phase-noise differentially tuned quadrature VCO design in standard CMOS , 2001, IEEE J. Solid State Circuits.

[14]  Michiel Steyaert,et al.  A 1.8-GHz low-phase-noise CMOS VCO using optimized hollow spiral inductors , 1997, IEEE J. Solid State Circuits.

[15]  A. Hajimiri,et al.  Design issues in CMOS differential LC oscillators , 1999, IEEE J. Solid State Circuits.

[16]  Sanjay Raman,et al.  Quality factor and inductance in differential IC implementations , 2002 .

[17]  S. Raman,et al.  A 0.35 /spl mu/m CMOS 2.5 GHz complementary -G/sub M/ VCO using PMOS inversion mode varactors , 2001, 2001 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium (IEEE Cat. No.01CH37173).

[18]  Yuan Taur,et al.  Fundamentals of Modern VLSI Devices , 1998 .

[19]  T. Manku,et al.  Microwave CMOS-device physics and design , 1999, IEEE J. Solid State Circuits.

[20]  A. Matsuzawa,et al.  RF-SoC-expectations and required conditions , 2002 .