Design and High-Fidelity Verification of an Energy-Efficient NAND-Like SAS-MRAM for ReLU-Activated Feature Caching in CNN CIM

Magnetic random-access memory (MRAM) is an emerging non-volatile memory technology distinguished by its radiation hardness, high endurance, and CMOS process compatibility, positioning it as a promising candidate to replace static random-access memory (SRAM). However, mainstream MRAM devices exhibit low cache efficiency in digital computing-in-memory (CIM) architectures due to the inherent incompatibility between their writing mechanism and the ReLU output data structure. This paper proposes a NAND-Like SAS-MRAM (NLSAS-MRAM), which shows extremely high efficiency when writing zero-dominated data, and is therefore highly suitable for caching ReLU outputs. To rigorously verify this advantage, we developed a high-fidelity co-simulation flow. Simulation results show that the proposed NLSASMRAM achieves a writing power consumption of only 35% that of STT-MRAM and 63% of SOT-MRAM. Furthermore, it delivers a 52.6× improvement in cache potential FOM over STT-MRAM and a 2.6× improvement over SOT-MRAM.