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A K-band low-noise bipolar class-C VCO for 5G backhaul systems in 55 nm BiCMOS technology.

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Title: A K-band low-noise bipolar class-C VCO for 5G backhaul systems in 55 nm BiCMOS technology.
Authors: Lacaita, Niccolò1 niccolo.lacaita@gmail.com, Bassi, Matteo1, Mazzanti, Andrea1, Svelto, Francesco1
Source: Integration: The VLSI Journal. Sep2018, Vol. 63, p299-305. 7p.
Subjects: Low noise amplifiers, Voltage-controlled oscillators, BiCMOS digital integrated circuits, Telecommunication systems, Electronic band structure
Abstract: Abstract The development of 5G communication systems is underway. When employing 64 QAM, very low phase noise levels are required to limit EVM - i.e. less than −117 dBc/Hz at 1 MHz offset from f = 20 GHz. In this paper, the challenges of achieving such a low phase noise are discussed in detail. The choice between CMOS vs BJT devices is investigated and the impact of the base resistance intrinsic in BJT-based VCOs is addressed. BJT-based VCO shows ∼2 dB better phase noise when compared to CMOS-based VCO and low supply is employed. When higher supply is leveraged, BJT-based VCO advantage is kept while CMOS-based VCO is not able to reach the targeted tuning range due to thick-oxide devices parasitics. Emphasis is on the minimization of L/Q inductor versus quality factor ratio, to further minimize phase noise. Prototypes in a 55 nm BiCMOS technology were operated at 2.5 V supply with the largest amplitude allowed by reliability constraints. Measurements show a phase noise as low as −119 dBc/Hz at 1 MHz from a 20 GHz carrier offset with a tuning range (TR) of 19% and FoM = −187 dBc/Hz. Power consumption is 56 mW. To the best of authors' knowledge, the presented VCO shows the lowest reported phase noise among state-of-the-art BiCMOS VCOs with TR>10%. Highlights • Minimization of L/Q ratio is key to achieve very low phase noise levels. • A comparison between class-B/class-C VCOs with BJT/MOS active devices is presented. • BJTs offer several advantages over CMOS for VCO design. • Trade-off between base resistance noise and tuning-range is addressed for BJT/MOS VCOs. • A class-C BJT-based VCO is presented with record phase noise. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
Description
Abstract:Abstract The development of 5G communication systems is underway. When employing 64 QAM, very low phase noise levels are required to limit EVM - i.e. less than −117 dBc/Hz at 1 MHz offset from f = 20 GHz. In this paper, the challenges of achieving such a low phase noise are discussed in detail. The choice between CMOS vs BJT devices is investigated and the impact of the base resistance intrinsic in BJT-based VCOs is addressed. BJT-based VCO shows ∼2 dB better phase noise when compared to CMOS-based VCO and low supply is employed. When higher supply is leveraged, BJT-based VCO advantage is kept while CMOS-based VCO is not able to reach the targeted tuning range due to thick-oxide devices parasitics. Emphasis is on the minimization of L/Q inductor versus quality factor ratio, to further minimize phase noise. Prototypes in a 55 nm BiCMOS technology were operated at 2.5 V supply with the largest amplitude allowed by reliability constraints. Measurements show a phase noise as low as −119 dBc/Hz at 1 MHz from a 20 GHz carrier offset with a tuning range (TR) of 19% and FoM = −187 dBc/Hz. Power consumption is 56 mW. To the best of authors' knowledge, the presented VCO shows the lowest reported phase noise among state-of-the-art BiCMOS VCOs with TR>10%. Highlights • Minimization of L/Q ratio is key to achieve very low phase noise levels. • A comparison between class-B/class-C VCOs with BJT/MOS active devices is presented. • BJTs offer several advantages over CMOS for VCO design. • Trade-off between base resistance noise and tuning-range is addressed for BJT/MOS VCOs. • A class-C BJT-based VCO is presented with record phase noise. [ABSTRACT FROM AUTHOR]
ISSN:01679260
DOI:10.1016/j.vlsi.2018.04.009