A Stacked-Complementary 5 GHz Oscillator With Even-Only Differential Harmonic Shaping Achieving −150 dBc/Hz Phase Noise at 10-MHz Offset Using Body-Biased Thin-Oxide 22-nm FDSOI

• Published in: IEEE solid-state circuits letters 2020, Vol.3, p.98-101
• Main Authors: El-Aassar, Omar, Rebeiz, Gabriel M.
• Format: Article
• Language: English
• Subjects: Common mode resonance; FDSOI CMOS; figure-of-merit (FoM); Frequency measurement; Harmonic analysis; Inductors; Logic gates; low phase noise; Metal oxide semiconductors; MOS devices; Noise sensitivity; Phase noise; Q factors; Topology; transformer
• ISSN: 2573-9603; 2573-9603
• DOI: 10.1109/LSSC.2020.3005799

This letter proposes a 5-GHz stacked-complementary oscillator (SCO) that uses high-quality factor ( Q ) single-turn nested differential inductors to achieve very low tank fundamental impedance R_{\mathrm{ Tank}} and even-harmonic shaping. The complementary nature of nMOS and pMOS is exploited to achieve second and fourth harmonic common-mode resonances using differential-only inductors with higher Q compared to the conventional single-ended tail filter. The complementary-stacked topology ensures the voltage between any two device terminals remains within reliable limits, while the body-bias is used to set the oscillator class with much lower noise sensitivity compared to the standard gate biasing. The SCO achieves < −150 dBc/Hz phase noise at 10-MHz offset across the tuning range from 4.75 to 5.4 GHz and a supply frequency pushing better than 20 MHz/V, while using thin-oxide devices operated from 0.6 V in a 22-nm technology node. The SCO meets the stringent phase noise requirements of the GSM standard while keeping a figure-of-merit (FoM) of 191-193 dBc/Hz at 10-MHz offset.