Robust and programmable Self-Timed Ring oscillators

This paper presents the design of configurable digital oscillators based on Self-Timed Rings. The oscillation frequencies are easily programmable and the oscillation mode, which can be peculiar in such kind of oscillator, can be controlled. In addition, a method to enhance the robustness to process variability is proposed. A test chip has been designed in CMOS 130 nm technology and the experimental results validate the relevance of our approach.