Fabrication of a magnetic tunnel junction-based 240-tile nonvolatile field-programmable gate array chip skipping wasted write operations for greedy power-reduced logic applications

A nonvolatile field-programmable gate array (NVFPGA) test chip with 240 tiles (the basic components) in a 12 x 20 2D-array is fabricated by 90 nm CMOS and 70 nm magnetic tunnel junction (MTJ) technologies. Since not only circuit configuration data but also temporal data are still remained in the MTJ devices even when the power supply is cut off, standby power dissipation is completely eliminated by utilizing tile-level power gating. Power reduction is further accelerated by skipping wasted write operations of nonvolatile flip-flops (NVFFs) for storing temporal data when the temporal data and the stored one are the same. As a typical application, a motion-vector prediction function is implemented on the proposed NVFPGA, which results in a write power reduction of 77% compared to that of a conventional MTJ-based NVFPGA and a total power reduction of 70% compared to that of an SRAM-based FPGA.