X-band NMOS and CMOS Cross-Coupled DCO’s with a “Folded” Common-Mode Resonator Exhibiting 188.5 dBc/Hz FoM with 29.5% Tuning Range in 16-nm CMOS FinFet

This paper presents two X-band state of the art digitally controlled oscillators (DCO's), one utilizes CMOS and the other NMOS as cross-coupled pairs. Both designs include a "folded" common-mode resonator in order to enhance performance while minimizing the required area. The implemented DCO's cover 9 to 12.1 GHz and 9.3 to 12.4 GHz for the NMOS and CMOS designs respectively, achieving a frequency tuning range (FTR) of 29.5%. Measured phase noise referred to 6.1 GHz and at 1 MHz offset is -118.5 and -114 dBc/Hz for NMOS and CMOS respectively. The NMOS design consumes 3.6 mW while the CMOS design consumes 1.1 mW both from a 0.8 V supply, obtained figure of merit (FoM) for both designs is higher than 188.5 dBc/Hz. Both designs are very compact with an area less than 0.054 mm2.