Measurement-Based Ring Oscillator Variation Analysis

As transistor size scales down, unavoidable process variations are rapidly increasing. Consequently, it's essential for designers to accurately estimate within-die and interdie variations so that circuits and integrated systems can operate correctly. This article describes an analysis of ring oscillators that were designed in 180-nm and 100-nm CMOS technologies, and discusses the oscillators' frequency variations as determined for different stage numbers and supply voltages.