Design of an STT-MTJ based true random number generator using digitally controlled probability-locked loop

This paper presents a design of a True Random Number Generator (TRNG) using a Spin Transfer Torque Magnetic Tunnel Junction (STT-MTJ) device. Since the probability of the STT-MTJ-based TRNG is locked using a digitally controlled feedback loop, the sensitivity of the feedback gain can be reduced greatly, which eliminates a high-gain amplifier in the feedback loop. It is demonstrated using the circuit simulator (NS-SPICE where the STT-MTJ model is established based on 90nm CMOS/MTJ process technologies) and MATLAB that the random sequences generated from the TRNG become 50%, where the gain of signal converters in the probability-locked loop is the precision of at most 9bit.