The Effect of Mismatches and Delay on the Quadrature Error of a Cross-Coupled Relaxation Oscillator

Fernandes, Jorge; Kouwenhoven, Marc; Bos, C. van den; Oliveira, Luís B.; Verhoeven, C.J.M.

doi:10.1109/tcsi.2007.906069

Cited by 11 publications

(7 citation statements)

References 8 publications

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“…Yet, there are attractive aspects of RC-oscillators: low area (inductors are not required), realization in a low-cost technology (several metal layers and a thick top metal layer, critical for high Q inductors, are not required), good quadrature accuracy (mismatches produce only second-order effects, due to coupling [4]). If all these aspects are taken into account, quadrature RC-oscillators can be considered, in some applications, as a viable alternative to LC-oscillators when minimization of area (and cost) is important.…”

Section: Discussionmentioning

confidence: 99%

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Experimental comparison of phase‐noise in cross‐coupled RC‐ and LC‐oscillators

Oliveira

Allam

Filanovsky

et al. 2009

Circuit Theory & Apps

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SUMMARYRelaxation RC-oscillators are notorious for their poor phase-noise performance. However, there are reasons to expect a phase-noise reduction in quadrature oscillators obtained by cross-coupling two relaxation oscillators. We present measurements on 5 GHz oscillators, which show that in RC-oscillators the coupling reduces both the phase-noise and quadrature error, whereas in LC-oscillators the coupling reduces the quadrature error, but increases the phase-noise. A comparison using standard figures of merit indicates that quadrature RC-oscillators may be a viable alternative to LC-oscillators when area and cost are to be minimized.

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Section: Discussionmentioning

confidence: 99%

“…Both RC- [3,4], and LC-oscillators [5][6][7][8][9] can be cross-coupled to provide quadrature outputs.…”

Section: Introductionmentioning

confidence: 99%

Experimental comparison of phase‐noise in cross‐coupled RC‐ and LC‐oscillators

Oliveira

Allam

Filanovsky

et al. 2009

Circuit Theory & Apps

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“…The first solution increases the quadrature error due to mismatches and parasitic effects. Therefore, the second solution is preferred as it is less influenced by these effects and also benefits from a 3 dB phase noise reduction [4] [5]. One common solution is to couple two LC oscillators.…”

Section: Iq Cross-coupled Rc Relaxation Vcomentioning

confidence: 99%

A 2.41 GHz ISM receiver using an IQ VCO-mixer

Ferreira

Fernandes

Goncalves

2015

2015 IEEE 13th International New Circuits and Systems Conference (NEWCAS)

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This paper presents an inductorless 2.41 GHz ISM receiver, implemented in a standard 130 nm CMOS technology. The receiver consists of a feedback LNA and an IQ VCO-mixer, designed for low area and low power. The VCO-mixer is based on an IQ cross-coupled RC relaxation VCO, where two single oscillators are coupled through active loads. This topology consumes approximately 20 % less power and reduces the area, in comparison to the commonly used soft-limiter coupling. The mixing function is incorporated in the IQ VCO, benefiting from an increased gain. The LNA is based on a shunt-shunt topology, where feedback is used for input impedance matching and gain desensitization. The LNA works both as RF signal amplifier and VCO-mixer's current mirror, reducing a third of the total VCOmixer's power consumption. The receiver front-end has a gain of 22.26 dB and a noise figure of 7.98 dB, occupying an area of 0.145 mm 2 and consuming 7.58 mW from a 1.2 V power supply.This work was supported by national funds through Fundação para a Ciência e a Tecnologia (FCT) with reference UID/

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“…To increase the bandwidth, a capacitor array can be used, but the switches' resistance may deteriorate the phase-noise, and extra circuitry is required. RC-oscillators have higher phase-noise than LC-oscillators, but they can have wide tuning range [11][12][13][14][15]. Being inductorless, they occupy a very small area, and they can be built in a low-cost CMOS technology, without RF options (several metal layers and thick top metal, required for high Q inductors).…”

Section: Introductionmentioning

confidence: 99%

An inductorless CMOS quadrature oscillator continuously tuneable from 3.1 to 10.6 GHz

Oliveira

Snelling²,

Fernandes

et al. 2012

Circuit Theory & Apps

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SUMMARYModern RF front-ends require wide tuning-range oscillators with quadrature outputs. In this paper we present a two-integrator quadrature oscillator, which covers the whole bandwidth of UWB applications. A circuit prototype in a 130 nm CMOS technology is continuously tuneable from 3.1 to 10.6 GHz. The circuit die area is less than 0.013 mm 2 , leading to a figure-of-merit FOMA of −176.7dBc/Hz at the upper frequency. The supply voltage is 1.2 V, and the power consumption is 7 mW at the lower frequency and 13 mW at the upper frequency.

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The Effect of Mismatches and Delay on the Quadrature Error of a Cross-Coupled Relaxation Oscillator

Cited by 11 publications

References 8 publications

Experimental comparison of phase‐noise in cross‐coupled RC‐ and LC‐oscillators

Experimental comparison of phase‐noise in cross‐coupled RC‐ and LC‐oscillators

A 2.41 GHz ISM receiver using an IQ VCO-mixer

An inductorless CMOS quadrature oscillator continuously tuneable from 3.1 to 10.6 GHz

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