A single-chip 900-MHz spread-spectrum wireless transceiver in 1-μm CMOS. I. Architecture and transmitter design

Rofougaran, A.; Chang, G.; Rael, J.J.; Chang, Jung Min; Rofougaran, M.; Chang, P.J.; Djafari, M.; Ku, Mong-Kai; Röth, Elizabeth; Abidi, A.A.; Samueli, H.

doi:10.1109/4.663557

Cited by 231 publications

(104 citation statements)

References 29 publications

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“…2 (c) in which the phase noise of proposed QVCO shows an improvement of 22 dB and 5 dB, compared with the QVCOs of [2] and [8], respectively. For a more complete and fair comparison, a Figure of Merit (FoM) such as the one proposed in [8] can be used:…”

Section: Simulation Results and Comparisonsmentioning

confidence: 99%

“…The simulated phase noise of the proposed QVCO and [2] and [8] are compared in Fig. 2 (c) in which the phase noise of proposed QVCO shows an improvement of 22 dB and 5 dB, compared with the QVCOs of [2] and [8], respectively.…”

Section: Simulation Results and Comparisonsmentioning

confidence: 99%

“…Andreani [3] proposed a modified version of the QVCO in [2], in which the coupling transistors are in series with the cross-connected transistors. This modified QVCO showed a significant phase noise improvement compared to that in [2], but the stacking of transistors in this topology limits the oscillation amplitude. Similarly the other LC-QVCOs proposed afterward by this group, used some sort of coupling elements, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…In the first LC-QVCO proposed by Rofougaran [2], four extra transistors are placed in parallel with the cross-connected transistors as coupling devices. Andreani [3] proposed a modified version of the QVCO in [2], in which the coupling transistors are in series with the cross-connected transistors.…”

Section: Introductionmentioning

confidence: 99%

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A new low-phase noise direct-coupled CMOS LC-QVCO

Ebrahimi

Naseh

2009

IEICE Electron. Express

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Abstract:A new LC quadrature voltage-controlled oscillator (LC-QVCO), made with direct coupling of two CMOS LC-VCOs, is presented. In the proposed circuit two identical cross-connected LC-VCOs are coupled together by directly connecting the bulk of the crossconnected transistors of one VCO to the bulk of the MOS varactors of the other VCO in such a way no extra devices are needed for coupling. Thus, no extra noise sources and power consumption are added to the core VCOs and results in high performance of QVCO. A Linear analysis of the circuit and the result of simulation in a 0.18 μm CMOS technology are presented. The same proposed coupling scheme can be used for multiphase signal generation as well. Simulation shows the proposed QVCO can operate with supply voltage as low as 0.5 V .

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Section: Simulation Results and Comparisonsmentioning

confidence: 99%

Section: Simulation Results and Comparisonsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A new low-phase noise direct-coupled CMOS LC-QVCO

Ebrahimi

Naseh

2009

IEICE Electron. Express

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“…Depending on their mechanism of operation, LC-QVCOs can be categorized in two main groups: first harmonic QVCOs [2] and superharmonic QVCOs [3,4,5,6,7,8,9]. In most of the QVCOs in the former group, oscillation frequency deviates from the LC-tank resonance frequency, leading to phase-noise degradation [11].…”

Section: Introductionmentioning

confidence: 99%

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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Analysis and review of main characteristics of Colpitts oscillators

Hemmati

Dehghani

2021

Circuit Theory & Apps

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Summary In this review, different topologies of CMOS Colpitts oscillators including single‐ended and differential configurations are studied, and the main specifications of them are presented. The studied LC tank Colpitts oscillators operating at gigahertz frequencies are categorized in several main structures to have more insight into their comparison. Also, the main characteristics of the Colpitts voltage‐controlled oscillators (VCOs) are compared and analyzed according to their configurations and calculated results of their transconductances. Besides, the Colpitts quadrature voltage‐controlled oscillators (QVCOs) realized by the mentioned VCOs are studied and categorized. Also, the various coupling techniques adopted in each QVCO to generate output signals with 90° phase differences are highlighted.

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A single-chip 900-MHz spread-spectrum wireless transceiver in 1-μm CMOS. I. Architecture and transmitter design

Cited by 231 publications

References 29 publications

A new low-phase noise direct-coupled CMOS LC-QVCO

A new low-phase noise direct-coupled CMOS LC-QVCO

New capacitive coupled superharmonic quadrature LC-VCO

Analysis and review of main characteristics of Colpitts oscillators

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