An Event-Driven Spiking Compute-In-Memory Macro based on SOT-MRAM

Abstract: The application of Magnetic Random-Access Memory (MRAM) in computing-in-memory (CIM) has gained significant attention. However, existing designs often suffer from high energy consumption due to their reliance on complex analog circuits for computation. In this work, we present a Spin-Orbit- Torque MRAM(SOT-MRAM)-based CIM macro that employs an event-driven spiking processing for high energy efficiency. The SOT-MRAM crossbar adopts a hybrid series-parallel cell structure to efficiently support matrix-vector multiplication (MVM). Signal information is (en) decoded as spikes using lightweight circuits, eliminating the need for conventional area- and powerintensive analog circuits. The SOT-MRAM macro is designed and evaluated in 28nm technology, and experimental results show that it achieves a peak energy efficiency of 243.6 TOPS/W, significantly outperforming existing designs.