Abstract
The ring oscillator has long been used as a process monitor inside an IC. However, its clock period is jointly affected by the PVT (Process, Voltage, and Temperature) conditions. In this work, we present a low-cost methodology that can make a ring oscillator an even more versatile monitor – for not only the process status, but also the temperature and the IR-drop traces in normal operation. To achieve this goal, our methodology heavily relies on the support of the software to perform two tasks - (1) PVT-aware clock period modeling of a given ring oscillator, and (2) PVT analysis that derives the temperature trace and the IR-drop trace inside an IC under monitoring considering process variation.