Phase Lock Loop based Temperature Compensation for MEMS Oscillators

Salvia, J.; Melamud, R.; Chandorkar, Saurabh A.; Lee, H.K.; Qu, Yu Qiao; Lord, Samuel J.; Murmann, Boris; Kenny, Thomas W.

doi:10.1109/memsys.2009.4805469

Cited by 18 publications

(6 citation statements)

References 15 publications

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“…The dc current results in Joule heating and temperature control of the resonator. A more direct and precise way of sensing the resonator temperature is based on the difference in TC of two resonance modes [185] or two separated resonators with different TCs [186]. A very high degree of frequency stability is achieved of only 0.1 ppm over 100 K by stabilizing the frequency difference of the two resonators with different TCs [186].…”

Section: Resonator Stability Temperature Drift and Agingmentioning

confidence: 99%

“…However, E-modulus engineering can easily be combined with other techniques to further improve the stability. The use of a Si-SiO 2 capacitive resonator in combination with oven control has been shown to result in very good temperature stability of only 0.1 ppm [186]. In [200], a stability of 20 ppm is obtained over a large temperature window of 100 K using a 1.5 GHz AlN-SiO 2 FBAR resonator in combination with temperature-dependent impedance loading.…”

Section: Resonator Stability Temperature Drift and Agingmentioning

confidence: 99%

See 1 more Smart Citation

A review of MEMS oscillators for frequency reference and timing applications

Beek¹,

Puers²

2011

J. Micromech. Microeng.

390

219

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MEMS-based oscillators are an emerging class of highly miniaturized, batch manufacturable timing devices that can rival the electrical performance of well-established quartz-based oscillators. In this review, a description is given of the key properties of a MEMS resonator that determine the overall performance of a MEMS oscillator. Piezoelectric, capacitive and active resonator transduction methods are compared and their impact on oscillator noise and power dissipation is explained. An overview is given of the performance of MEMS resonators and MEMS-based oscillators that have been demonstrated to date. Mechanisms that affect the frequency stability of the resonator, such as temperature-induced frequency drift, are explained and an overview is given of methods that have been demonstrated to improve the frequency stability. The aforementioned performance indicators of MEMS-based oscillators are benchmarked against established quartz and CMOS technologies.

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Section: Resonator Stability Temperature Drift and Agingmentioning

confidence: 99%

Section: Resonator Stability Temperature Drift and Agingmentioning

confidence: 99%

A review of MEMS oscillators for frequency reference and timing applications

Beek¹,

Puers²

2011

J. Micromech. Microeng.

390

219

View full text Add to dashboard Cite

show abstract

“…Active compensation technologies, such as electronic phase-locked loop (PLL) and oven storage, have been widely applied. For instance, Salvia et al achieved ±0.05 ppm by PLL technology and Kwon et al achieved ±1.5 ppb by oven storage around the 100 °C range [ 28 , 29 ]. The drawbacks of an active approach are the inevitable circuit complexity and power consumption caused by additional sensors.…”

Section: Introductionmentioning

confidence: 99%

Temperature Characteristics of a Contour Mode MEMS AlN Piezoelectric Ring Resonator on SOI Substrate

Fei

Ren

2021

Micromachines

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As a result of their IC compatibility, high acoustic velocity, and high thermal conductivity, aluminum nitride (AlN) resonators have been studied extensively over the past two decades, and widely implemented for radio frequency (RF) and sensing applications. However, the temperature coefficient of frequency (TCF) of AlN is −25 ppm/°C, which is high and limits its RF and sensing application. In contrast, the TCF of heavily doped silicon is significantly lower than the TCF of AlN. As a result, this study uses an AlN contour mode ring type resonator with heavily doped silicon as its bottom electrode in order to reduce the TCF of an AlN resonator. A simple microfabrication process based on Silicon-on-Insulator (SOI) is presented. A thickness ratio of 20:1 was chosen for the silicon bottom electrode to the AlN layer in order to make the TCF of the resonator mainly dependent upon heavily doped silicon. A cryogenic cooling test down to 77 K and heating test up to 400 K showed that the resonant frequency of the AlN resonator changed linearly with temperature change; the TCF was shown to be −9.1 ppm/°C. The temperature hysteresis characteristic of the resonator was also measured, and the AlN resonator showed excellent temperature stability. The quality factor versus temperature characteristic was also studied between 77 K and 400 K. It was found that lower temperature resulted in a higher quality factor, and the quality factor increased by 56.43%, from 1291.4 at 300 K to 2020.2 at 77 K.

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“…It was demonstrated that frequency accuracy at the ppm level and temperature stability can be achieved with frequency synthesizer techniques, the drawback of which is the relatively high power. The power of the frequency synthesized MEMS oscillator is approximately 10 times larger than those of quartz crystal oscillators of the same level owing to the increased powers of the phase-locked loop (PLL) circuits, and limits its applications [6][7][8][9][10][11][12]. Low-power techniques are required for both frequency tuning and temperature stabilization.…”

Section: Introductionmentioning

confidence: 99%

Oven-Controlled MEMS Oscillator with Integrated Micro-Evaporation Trimming

Pei

Sun

Yang

et al. 2020

Sensors

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This study reports an oven-controlled microelectromechanical systems oscillator with integrated micro-evaporation trimming that achieves frequency stability over the industrial temperature range and permanent frequency trimming after vacuum packaging. The length-extensional-mode resonator is micro-oven controlled and doped degenerately with phosphorous to achieve a frequency instability of ±2.6 parts per million (ppm) in a temperature range of −40 to 85 °C. The micro-evaporators are bonded to the resonator, integrated face-to-face, and encapsulated in vacuum. During trimming, the micro-evaporators are heated electrically, and the aluminum layers on their surfaces are evaporated and deposited on the surface of the resonator that trims the resonant frequency of the resonator permanently. The impact of the frequency trimming on the temperature stability is very small. The temperature drift increases from ±2.6 ppm within the industrial temperature range before trimming to ±3.3 ppm after a permanent trimming of −426 ppm based on the local evaporation of Al. The trimming rate can be controlled by electric power. A resonator is coarse-trimmed by approximately −807 ppm with an evaporation power of 960 mW for 0.5 h, and fine-trimmed by approximately −815 ppm with an evaporation power of 456 mW for 1 h. Though the Q-factor decreases after trimming, a Q-factor of 304,240 is achieved after the trimming of −1442 ppm.

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Phase Lock Loop based Temperature Compensation for MEMS Oscillators

Cited by 18 publications

References 15 publications

A review of MEMS oscillators for frequency reference and timing applications

A review of MEMS oscillators for frequency reference and timing applications

Temperature Characteristics of a Contour Mode MEMS AlN Piezoelectric Ring Resonator on SOI Substrate

Oven-Controlled MEMS Oscillator with Integrated Micro-Evaporation Trimming

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