Oscillators are essential building blocks in many applications. For instance, they arebasic blocks in almost all designs: they are part of PLLs, clock recovery systems andfrequency synthesizers. The design of a low phase-noise multi-phase clock circuitry isespecially crucial when a large number of phases is required. There are plenty of workscovering the design of multiphase clocks. High frequency oscillators can be implementedusing ring structures, relaxation circuits or LC circuits. Ring architectures can easily providemultiple clocks with a small die size. With the advanced nanometric technologies, it is alsorequired to deal with the process variability, stability and phase noise. Today many studiesare oriented to Self-Timed Ring (STR) oscillators which present well-suited characteristicsfor managing process variability and offering an appropriate structure to limit the phasenoise. Therefore, self-timed rings are considered as promising solution for generatingclocks.This thesis studies the benefits and potential offered by Self-Timed Ring oscillators.Two main applications have been identified. On the one hand, these oscillators are apromising solution for the generation of high-frequency multi-phase low phase noise clocks.On the other hand, they are a simple alternative to some extent to the conventionaloscillators and DLLs, because they are digitally programmable. Several oscillators havebeen designed, implemented, manufactured in 65 nm CMOS technology fromSTMicroelectronics, and characterized. This work has demonstrated the relevance of theseoscillators, which are a serious alternative to the conventional ring oscillators based oninverters.
