A perpendicular magnetic tunnel junction (P-MTJ)-based one-transistor/one- resistor (1T-1R) binary content-addressable memory (CAM) is proposed for a high-density nonvolatile CAM. The proposed CAM cell performs an equality-search operation between an input bit and the corresponding stored bit by detecting the difference of a "cell resistance", where the cell resistance is determined by the series connection of one metal-oxide-semiconductor (MOS) transistor and one P-MTJ device. This circuit structure makes it possible to implement a compact nonvolatile CAM cell circuit with 1.25 μm2 of a cell size in a 0.14μm complementary MOS (CMOS)/P-MTJ process. Moreover, the equality-search operation in a bit-serial fashion is used for great reduction of the activity rate in the proposed CAM cell array, since most of the mismatched words in the CAM are detected by just several higher bits of comparison results in the word circuits. By applying a bit-level fine-grained power gating scheme, a fabricated 64-bit × 128-word nonvolatile CAM achieves high density with maintaining low search energy under 3.1% of activity rate in the cell array.
ASJC Scopus subject areas
- Physics and Astronomy(all)