An 11-15.8GHz Class-D DCO with-117.5 dBc/Hz Phase Noise at 1 MHz Offset in 22nm FDSOI CMOS Technology

In this paper, an NMOS core LC-tuned DCO with Class-D operation is optimized to achieve superior phase noise applicable to WiFi 6E 6G band frequency synthesizers. A modified second harmonic filter is proposed to reduce unexpected impact from power and ground plane parasitic inductance so that simulations agree well with measurements. Developed in 22nm FDSOI technology, this design takes advantage of back gate control to boost the quality factor of tuning cap arrays. The DCO ranging from 11GHz to 15.8GHz achieves a phase noise of -117.54 dBc/Hz at 1MHz offset from the 12.78GHz carrier frequency with an FoM of -187.8dBc/Hz and a tuning range of 35.8%.