A Phase-Change Via-Reconfigurable CMOS LC VCO.

This paper demonstrates the efficacy of phase-change (PC) vias in reconfiguring RF front-end circuits for multiband/multi-standard operation. Constructed using two series-connected (SC) GeTe vias, a PC switch can be reversibly transformed between a high R{OFF} state and a low R{ON} state within 1 \mus. Using such PC switches to switch the inductor in a resonator, two LC voltage-controlled oscillators (VCOs) based on: 1) a SC and 2) a coupling-controlled (CC) resonator are developed. Designed and fabricated in 0.13-\mum CMOS in conjunction with an in-house GeTe process, the VCOs can switch their operating frequency over widely separated bands. Wide tuning ranges of 2.89–4.23/(4.93–7.79) and 4.80–8.53/(5.28–10.20) GHz were achieved in the off/on state for the SC/(CC) VCOs. The measured phase noise over the entire tuning range was lower than -103.4 and -102.7~dBc/Hz, at a 1-MHz offset frequency, respectively. [ABSTRACT FROM AUTHOR]