A Ring-Oscillator-based Odometer to Unveil the Actual IC Usage Time

Abstract

Traditionally, on-chip odometers have been utilized to monitor circuit aging for characterization or mitigation. However, modern applications, such as anticounterfeiting, demand odometers that not only track degradation but also accurately assess the circuit’s actual usage time and operating conditions. To meet these demands, the exploiting of the differing dynamics of key physical degradation mechanisms has been proposed. Unlike existing solutions, which require separate circuits for each degradation mechanism, this paper presents a more efficient approach. We introduce a novel ring oscillator-based odometer that takes advantage of the asymmetric stress of multiple degradation mechanisms. Central to this innovation is a newly developed processing block, the duty cycle-dependent frequency divider. This design enables the circuit to infer degradation data from two distinct mechanisms, positioning it as an ideal solution to monitor circuit usage over time.