Predicting circuit aging using ring oscillators

Abstract—This paper presents a method for inferring circuit delay shifts due to bias temperature instability using ring oscillator (ROSC) sensors. This procedure is based on presilicon analysis, postsilicon ROSC measurements, a new aging analysis model called the Upperbound on fMax (UofM), and a look-up table that stores a precomputed degradation ratio that translates delay shifts in the ROSC to those in the circuits. This method not only yields delay estimates within 0.2 % of the true values with very low runtime, but is also independent of temperature and supply voltage variations. I