  Many emerging alternative models of computation require massive numbers of
random bits, but their generation at low energy is currently a challenge. The
superparamagnetic tunnel junction, a spintronic device based on the same
technology as spin torque magnetoresistive random access memory has recently
been proposed as a solution, as this device naturally switches between two easy
to measure resistance states, due only to thermal noise. Reading the state of
the junction naturally provides random bits, without the need of write
operations. In this work, we evaluate a circuit solution for reading the state
of superparamagnetic tunnel junction. We see that the circuit may induce a
small read disturb effect for scaled superparamagnetic tunnel junctions, but
this effect is naturally corrected in the whitening process needed to ensure
the quality of the generated random bits. These results suggest that
superparamagnetic tunnel junctions could generate truly random bits at 20
fJ/bit, including overheads, orders of magnitudes below CMOS-based solutions.
