Performance of a resistance-to-voltage read circuit for sensing magnetic tunnel junctions

Magnetic tunnel junction devices represent state in the form of a magnetic field that is accessed as a resistance. Read circuits are needed to sense this state and to produce a digital logic voltage output. We designed a resistance-to-voltage read circuit for this purpose. This paper presents area, transient response, power, and jitter characterizations in a 3M2P 0.5 μm process and compares these results to a second implementation in a 5M1P 0.18 μm process. As the process scales down to smaller dimensions, area decreases, rise/fall times decrease, propagation times decrease, maximum frequency increases, power consumption decreases, and jitter decreases. We then evaluate the quality of phase measurements between read circuits for assessing clock skew in systems that use magnetic global clocking. Phase delays above 1.25 ns can be detected and are linear above 2 ns.