A Low-Power Hybrid RO PUF With Improved Thermal Stability for Lightweight Applications

• Published in: IEEE transactions on computer-aided design of integrated circuits and systems 2015-07, Vol.34 (7), p.1143-1147
• Main Authors: Yuan Cao, Le Zhang, Chip-Hong Chang, Shoushun Chen
• Format: Article
• Language: English
• Subjects: hardware security; Inverters; Physical Unclonable Function; process variation; Radiation detectors; ring oscillator; Semiconductor device measurement; Temperature measurement; temperature stability; Thermal stability; Transistors
• ISSN: 0278-0070; 1937-4151
• DOI: 10.1109/TCAD.2015.2424955

Ring oscillator (RO)-based physical unclonable function (PUF) is resilient against noise impacts, but its response is susceptible to temperature variations. This paper presents a low-power and small footprint hybrid RO PUF with a very high temperature stability, which makes it an ideal candidate for lightweight applications. The negative temperature coefficient of the low-power subthreshold operation of current starved inverters is exploited to mitigate the variations of differential RO frequencies with temperature. The new architecture uses conspicuously simplified circuitries to generate and compare a large number of pairs of RO frequencies. The proposed nine-stage hybrid RO PUF was fabricated using global foundry 65-nm CMOS technology. The PUF occupies only 250 μm 2 of chip area and consumes only 32.3 μW per challenge response pair at 1.2 V and 230 MHz. The measured average and worst-case reliability of its responses are 99.84% and 97.28%, respectively, over a wide range of temperature from -40 to 120 °C.