A Highly Reliable Physical Unclonable Function Based on 2T Voltage Reference and Diode-Clamped Comparator

In this paper, we present a novel physical unclonable function (PUF) structure based on 2T voltage reference and diode-clamped comparator. The proposed PUF implementation includes an array of the aforesaid 2T voltage references with same transistor size and layout design. Meanwhile, the output voltage variation mainly caused by the CMOS process variation can be well-extracted by the adopted diode-clamped comparator to generate a digital bit stream (256 bit) with excellent randomness. By utilizing the sub-threshold 2T voltage reference's superior stability to the environmental variations (e.g. operating temperature, supply voltage), the proposed implementation exhibits ultra-high reliability against wide-range operating temperature and supply voltage. This design is validated by our extensive post-layout simulations based on 65nm standard CMOS process, the average reliability is reported to be 99.88% and 99.37% for the operating temperature ranging from −40°C to 120°C and the supply voltage ranging from 0.8V to 1.8V, respectively. In addition, the overall power consumption is reduced to 3.1µW at a throughput of 10 Mb/s. Moreover, the superior unpredictability (i.e. randomness) of this design is verified by passing both the auto-correlation test and NIST randomness test.