Hardware true random number generators (TRNGs) yield random numbers from physical processes. Traditionally, such devices are based on statistically random events such as thermal noise or other quantum phenomena. In this brief, we propose a novel TRNG design using a spin-transfer torque magnetic tunnel junction (MTJ) device. Our solution exploits the stochastic nature of the MTJ switching, and the behavior of an xor gate dealing with probabilistic signals. We show that by using multiple MTJ devices, the proposed TRNG succeeds in filtering the negative effect of environmental changes as well as fabrication-induced variability and generates random sequences with high-entropy under any conditions.
Large-scale parameter characterization of Physical Unclonable Functions (PUFs) is of paramount importance in order to assess the quality and thus the suitability of such PUFs which would then be developed as an industrial-grade solution for hardware root of trust. Carrying out a proper characterization requires a large number of devices that need to be repeatedly sampled at various conditions. These prerequisites make PUF characterization process a very time-consuming and expensive task. Our work presents a dataset for the study of SRAM-based PUFs on microcontrollers; it includes full SRAM readouts along with internal voltage and temperature sensors of 84 microcontrollers of STM32 type. Data has been gathered with a custom-made and open platform designed for the automatic acquisition of SRAM readouts of such devices. This platform also provides possibilities of experimenting aging and reliability properties.
Process variability is becoming a major challenge in CMOS design of general and embedded SRAMs in particular due to continuous device scaling. The main problems are the increased static power and reduced operating margins, robustness and reliability. A common way to reduce the static power consumption of an SRAM memory array is to decrease its supply voltage when in memory retention mode. However, this leads to a further reduction in memory robustness. The most common tool for statistical analysis of circuits under process variability is standard Monte Carlo simulation which has been proven to be too expensive when applied on an ultra dense SRAM. In this paper a statistical robustness analysis method is proposed based on decoupling statistical integration from robustness region determination in the parameter domain. The robustness is estimated with a ~ 556X speed up relation to Monte Carlo and an error of ~ 1%.
5 October 2017 in International Journal of Circuit Theory and Applications
The power, reliability and technological issues of today's memories have led to intensive research of emergent memory technologies and emerging computing paradigms. One of the most promising emerging technology solution is the Spin-Transfer-Torque Magnetic Random Access Memories (STT-MRAMs). It has the great advantage of favoring increasing system complexity and performance, while being CMOS compatible. Computation paradigms, such as neuromorphic computing, unfeasible a few years back due to technological limitations, can take profit from this technology. In this paper we investigate the effect of meaningful MTJ reliability issues on the behavior of a fully-connected, single layer, MTJ-based Spiking Neural Network designed for character recognition.