A Revolving Reference Odometer Circuit for BTI-Induced Frequency Fluctuation Measurements under Fast DVFS Transients and Reconfigurable Feed Forward MUX PUF Design

Abstract

The frequency shift due to fast Bias Temperature Instability (BTI) related fast Dynamic Voltage and Frequency Scaled (DVFS) stress-recovery effects were measured using a high resolution revolving reference silicon odometer. It uses eight fresh/reference ring oscillators (ROSCs), which alternately take measurements three times making a maximum of 24 measurements. Thus the reference ROSCs undergo negligible stress and provide high measurement resolution, low measurement time and fast measurement step coupled with reliable measurements. For the first time, this design provides DVFS frequency shift measurement only in 1µs period after the supply transition. The test chip was implemented in a 65nm process. The frequency shift measurements were observed across different voltage supply, temperature, stress time duration, and supply ramp duration.