An impact of process variation on supply voltage dependence of logic path delay variation

Dynamic Voltage and Frequency Scaling (DVFS) technique requires accurate observation of critical path delay for robust operation under aggressive supply voltage scaling. Logic paths contain several types of logic gates and path delay have voltage dependences because different logic gates have different voltage dependences. However, it is not well investigated that how the voltage dependence of the path delay changes induced by process variation. This paper describes the effect of the process variation on the voltage dependence of path delay. Ring Oscillator circuits fabricated in 65-nm CMOS process are used for the evaluation and analysis of the process variation dependence of the voltage delay curves.