High frequency 65nm CMOS LC oscillators for inductor quality factor verification
Herzog, Hans (2013)
2013
Signaalinkäsittelyn ja tietoliikennetekniikan koulutusohjelma
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
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Hyväksymispäivämäärä
2013-06-05
Julkaisun pysyvä osoite on
http://urn.fi/URN:NBN:fi:tty-201306101192
http://urn.fi/URN:NBN:fi:tty-201306101192
Tiivistelmä
High quality factor inductors are essential for the design of low phase noise LC oscillators which play an important role in the transceivers of wireless communication devices. The reception capabilities of a radio frequency receiver are to great extent defined by the phase noise performance of the local oscillator. It is therefore important for modern single chip fully integrated transceiver design that high quality inductors are available and well modeled.
In this work we investigate the possibility of evaluating the quality factor of an inductor by the phase noise it generates when used in a reference oscillator. A differential CMOS LC oscillator is designed for inductor test benching. The designed oscillator is fabricated on a 65nm CMOS process with two different inductor designs with simulated quality factors of 7.4 and 10.2. The overall combined silicon area of the two oscillators including inductors and probing pads is 680μm by 510μm. The oscillation frequencies are dictated by the designed inductors and were measured 3.04GHz and 4.56GHz. The oscillators achieve a phase noise of -125dBc/Hz and -124dBc/Hz at 1MHz offset with 14mW and 16mW power dissipation respectively. An oscillator phase noise model is fitted to the measured phase noise data of both oscillators and the model parameters are compared. The received quality factors for the designed inductors are 8.2 ± 0.8 and 10.8 ± 0.6 respectively. It was found that the measured phase noise is in good agreement with the results predicted by the model and the relative quality factor can, with certain limitations, be estimated through relative phase noise measurements.
In this work we investigate the possibility of evaluating the quality factor of an inductor by the phase noise it generates when used in a reference oscillator. A differential CMOS LC oscillator is designed for inductor test benching. The designed oscillator is fabricated on a 65nm CMOS process with two different inductor designs with simulated quality factors of 7.4 and 10.2. The overall combined silicon area of the two oscillators including inductors and probing pads is 680μm by 510μm. The oscillation frequencies are dictated by the designed inductors and were measured 3.04GHz and 4.56GHz. The oscillators achieve a phase noise of -125dBc/Hz and -124dBc/Hz at 1MHz offset with 14mW and 16mW power dissipation respectively. An oscillator phase noise model is fitted to the measured phase noise data of both oscillators and the model parameters are compared. The received quality factors for the designed inductors are 8.2 ± 0.8 and 10.8 ± 0.6 respectively. It was found that the measured phase noise is in good agreement with the results predicted by the model and the relative quality factor can, with certain limitations, be estimated through relative phase noise measurements.