A 1-V 3.8-5.7-GHz wide-band VCO with differentially tuned accumulation MOS varactors for common-mode noise rejection in CMOS SOI technology

Fong, N.; Plouchart, J.-O.; Zamdmer, N.; Liu, Duixian; Wagner, L.; Plett, C.; Tarr, N. G.

doi:10.1109/tmtt.2003.815273

Cited by 87 publications

(49 citation statements)

References 12 publications

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“…In the proposed circuit, differential tuning MOS varactors [6,7] are used to avoid the drawbacks of high sensitivity effect. The differential tuning can be used to reject common-mode noise, and thus reducing the upconversion of low-frequency noise [5]. In the proposed VCO, high Q resonator tends to reduce the phase noise, and less active devices used to generate more differential negative resistance reduces the device noise sources to be upconverted to phase noise of VCO.…”

Section: Circuit Designmentioning

confidence: 99%

See 1 more Smart Citation

A 6 GHz low power differential VCO

Jang¹,

Lee²,

Chiu³

et al. 2006

Micro & Optical Tech Letters

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where n core and n clad are the effective index of core and cladding modes, respectively. ⌳ and m are the grating period and the cladding mode order, respectively. Since the hole-assisted fiber with large size of air holes has small area of cladding region, it has small effective index of cladding modes compared with that with small size of air holes. Accordingly, the wavelength spacing increases as the air hole size increases as seen in (1), which was measured to be changed in the range from 2.0 to 2.28 nm corresponding to air hole size. As seen in Figure 2, the number of peaks due to the cladding mode coupling was extremely reduced due to the reduction of the number of cladding modes. CONCLUSIONWe investigated the suppression of cladding mode coupling loss of FBGs fabricated with hole-assisted fibers, which has a germaniumdoped core and one-layered air holes in the silica cladding. Since the confinement of cladding modes becomes weak due to the reduction of the cladding diameter induced by air holes, higher order cladding modes cannot be supported by hole-assisted fibers because of air holes and the interaction between core and cladding modes through FBGs is reduced. Accordingly, air holes of FBGs fabricated with hole-assisted fibers could reduce the cladding mode coupling loss remarkably. The suppression of cladding mode coupling of less than ϳ0.33 dB and a 3 dB bandwidth of less than ϳ0.13 nm have been achieved. The wavelengths spacing between the main peak due to the core mode coupling and the first side peak due to the first order cladding mode coupling was changed in the range from 2.0 to 2.28 nm as the air holes size increases since the effective index of cladding mode is reduced by the air hole size within the fiber. The number of side peaks in the shorter wavelength induced by cladding mode coupling was also reduced.

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Section: Circuit Designmentioning

confidence: 99%

“…The proposed VCO topology has advantage over other topologies for low phase noise and high frequency operation while dissipating small power. The differentially tuned MOS varactors [5,6] are used to tune the output frequency with low phase noise. In section 2, the circuit operating principle used in VCO implementation will be described.…”

Section: Introductionmentioning

confidence: 99%

A 6 GHz low power differential VCO

Jang¹,

Lee²,

Chiu³

et al. 2006

Micro & Optical Tech Letters

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“…Integrated voltage controlled capacitors, varactors, are used in radiofrequency integrated circuits (RFICs) to implement tunable filters [1,2], frequency multipliers [3] or VCOs [4][5][6][7]. An integrated varactor can be implemented with the MOS capacitor (MOSVAR) [8][9][10] or PN junction diode (JVAR) [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Capacitive model for integrated PN varactors of cells with N⁺ buried layer

Marrero-Martín

Garcı́a

González

et al. 2010

Int J Numerical Modelling

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SUMMARYThis paper is devoted to analyzing varactors based on PN junction cells in order to obtain a capacitance model for radiofrequency (RF) applications. A cell is the minimum structure that can be considered a varactor, including all necessary layers and connections. Then, a specific capacitance for a RF integrated circuit is obtained overlapping all necessary cells horizontally and vertically. Our model estimates the total capacitance in a varactor, from both ports, considering all relevant internal contributions. Ten varactors based on the same cell have been designed and fabricated in 0.35 mm SiGe technology. These novel structures were also measured on-wafer for frequencies ranging between 0.5 and 10 GHz, and voltages varying from 0 to À5 V. Our model predicts the capacitances in all cases with relative errors smaller than 10%.

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“…However, the design is costly when compared with 0.35 lm lithography. A recent work with SOI CMOS presents a 5.8 GHz VCO implementation with a 2.56 GHz tuning range [9]. A 2115 dBc/Hz phase noise at 1 MHz offset is remarkably low when considering the high tuning range.…”

Section: Introductionmentioning

confidence: 99%