Fully-Digital Broadband Calibration-Less Impedance Monitor for Probe Insertion Detection against Power Analysis Attacks

In this work, a broadband supply impedance monitor is proposed to detect insertion of probing devices or package/PCB modifications in secure systems. The fully-digital architecture allows automated and portable design, and its compact area allows under-pad placement for inexpensive adoption. Ratiometric measurements suppress variations at no calibration, temporal zooming enhances sensitivity to reactance. Detection of several attacks with different probing devices is demonstrated with a 28-nm testchip up to 2 GHz.