Ring oscillators: The asynchronous alternative

Self-timed rings (STR) are promising approach for designing high-speed serial links and clock generators. Indeed, the architecture of STRs presents well-suited characteristics for managing process variability and offering an appropriate structure to limit the phase noise. Therefore, STRs are considered as promising solution for generating Multiphase clocks. Moreover, Self-Timed Rings can easily be configured to change their frequency by controlling their initialization at reset time. A test chip has been designed and fabricated in STMicroelectonics CMOS65nm technology to verify the theoretical claims and validate the simulation results.