Design of an MTJ-based nonvolatile lookup table circuit using an energy-efficient single-ended logic-in-memory structure

A 6-input nonvolatile lookup table (LUT) circuit is proposed using an energy-efficient single-ended logic-in-memory (LIM) structure in conjunction with a magnetic tunnel junction (MTJ) device. While the use of a conventional single-ended LIM structure makes the multi-input LUT circuit compact, a long delay due to the small difference in the MTJ resistance and a large amount of dynamic power consumption due to a DC current path are unavoidable. To overcome the problem, a PMOS feedback transistor which makes it possible to accelerate the logic operation is utilized in the proposed LUT circuit. The use of the PMOS feedback transistor also makes it possible to reduce dynamic power consumption by automatically cutting off the DC current just after logic value `0´ is read. In fact, the power-delay product of the proposed 6-input LUT circuit is reduced by 66% in comparison with that of the conventional single-ended one under a 90-nm CMOS technology.