High-Speed Tunable Generation of Random Number Distributions Using Actuated Perpendicular Magnetic Tunnel Junctions

TL;DR

This paper demonstrates that actuated perpendicular magnetic tunnel junctions can generate high-speed, tunable, and high-quality random number distributions, with controllable bias and stability considerations, suitable for true random number generation applications.

Contribution

It introduces a method to tune and analyze the quality of random numbers generated by pMTJs at high speed, highlighting their potential for TRNG applications.

Findings

Pulse amplitude controls probability bias.

Two XOR operations produce uniform 8-bit distributions.

Long-term bias correlates with pMTJ resistance.

Abstract

Perpendicular magnetic tunnel junctions (pMTJs) actuated by nanosecond pulses are emerging as promising devices for true random number generation (TRNG) due to their intrinsic stochastic behavior and high throughput. In this work, we study the tunability and quality of random-number distributions generated by pMTJs operating at a frequency of 104 MHz. First, changing the pulse amplitude is used to systematically vary the probability bias. The variance of the resulting bitstreams is shown to follow the expected binomial distribution. Second, the quality of uniform distributions of 8-bit random numbers generated with a probability bias of 0.5 is considered. A reduced chi-square analysis of this data shows that two XOR operations are necessary to achieve this distribution with p-values greater than 0.05. Finally, we show that there is a correlation between long-term probability bias variations and pMTJ resistance. These findings suggest that variations in the characteristics of the pMTJ underlie the observed variation of probability bias. Our results highlight the potential of stochastically actuated pMTJs for high-speed, tunable TRNG applications, showing the importance of the stability of pMTJs device characteristics in achieving reliable, long-term performance.