|BUCCOLERI FRANCESCO||Cycle: XXXV |
Tutor: SOTTOCORNOLA SPINELLI ALESSANDRO
Advisor: LACAITA ANDREA LEONARDO Major Research topic
:Analysis and design of low-noise LC-oscillator frequency references in 28nm CMOS technologyAbstract:
The Voltage Controlled Oscillator (VCO) is a key building block in high performance communication systems being the bottleneck for jitter minimization in modern frequency synthesizers. For this reason, in the last decades VCO research had attracted a great interest aiming at understanding the detailed conversion mechanisms of each noise source. Nowadays, the origin of the white noise contributions to the phase noise of each single VCO core are well known. They are minimized ensuring the maximum output voltage oscillation, which is ultimately limited by the available supply voltage. On the other hand, even if flicker noise gives a significant contribution to the total jitter, a complete understanding of the up-conversion mechanisms into phase noise is still missing.
The aim of this Ph.D. project is twofold: (i) to circumvent the limitations set by the supply voltage to the jitter generated by white noise investigating system level approaches, such as the combination of signals from multiple VCOs locked to the same reference. In this way, being the white noise of each core uncorrelated to each other, the signal to noise ratio can be improved beyond the single core performance.
(ii) to investigate further the flicker up-conversion phenomena in single core VCOs providing a formal background to some of the flicker noise minimization technique qualitatively proposed in literature. Based on the theoretical results, some novel flicker noise reduction techniques may be introduced, thus improving the state of the art.