A Fully-Digital Variation-Tolerant Runtime Detector for PCB-Level Probing Attack in a 28-nm CMOS

This letter presents the first on-chip detector for monitoring a PCB-level probing attack in 28-nm CMOS based on a time-to-digital converter (TDC). It can detect a probing attempt caused by placing a probe with a loading capacitance as small as 2 pF, encompassing most commercial passive probes. It also does so robustly across 30°C–90°C and 0.8–0.9 V, up to the data rate of 160 Mb/s during runtime. The proposed detector is integrated with a general-purpose digital output cell. It consumes $3910 ~\mu \text{m} ^{\mathrm{ 2}}$ and $36.8 ~\mu \text{W}$ at 40 Mb/s.