A 40nm STT-MRAM Near-Memory Computing Macro for Memory-Augmented Neural Network Acceleration

Memory-augmented neural network (MANN) has gained attention as a pivotal solution for few-shot learning (FSL). Among the candidates for associative memory in MANN accelerators, spin-transfer torque magnetic random-access memory (STT-MRAM) stands out for its compact cell area, long data retention time, and excellent scalability. In this paper, we propose an STT-MRAM near-memory computing (NMC) macro for MANN acceleration. The macro contains following innovations: 1) An array-level parallel computing architecture for L1 distance calculation. 2) A low-area-overhead memory-invert coding technique to reduce write energy consumption. 3) A configurable dynamic offset-compensation sense amplifier (CDOC-SA) to improve classification accuracy. Fabricated in 40nm CMOS process, our macro demonstrates an energy efficiency of 6.47 TOPS/W, achieving the classification accuracy of 98.3% and 93% for 8-way-5-shot tasks and 16-way-5-shot tasks on the Omniglot dataset.