Design of an MTJ-based nonvolatile multi-context ternary content-addressable memory

In this paper, we present for the first time a design of multi-context ternary content-addressable memory (MC-TCAM) based on CMOS/magnetic tunnel junction (MTJ) devices. TCAMs are one of associative memories that realize fast search operations, where the applications are IP lookup engines and memory-based approximate computing. The multi-context capability is realized using a shared comparison circuit with multiple MTJ-based nonvolatile storage elements, resulting in a high memory density and a low static power dissipation. In addition, a CMOS-based cross-coupled circuit makes it possible to realize fast switching speed and low power dissipation, where the area overhead is negligible because of the shared structure. The proposed nonvolatile MC-TCAM with a 128 x 64 array of four contexts is designed using TSMC 65-nm CMOS and an MTJ model, which achieves a 2.6 x faster search speed and a 90−97% search-energy reduction in comparison with a single-context nonvolatile TCAM.