15.3 A 351TOPS/W and 372.4GOPS Compute-in-Memory SRAM Macro in 7nm FinFET CMOS for Machine-Learning Applications
Qing Dong, Mahmut E. Sinangil, Burak Erbagci, Dar Sun, Win-San Khwa, Hung-Jen Liao, Yih Wang, Jonathan Chang
Abstract
Compute-in-memory (CIM) parallelizes multiply-and-average (MAV) computations and reduces off-chip weight access to reduce energy consumption and latency, specifically for Al edge devices. Prior CIM approaches demonstrated tradeoffs for area, noise margin, process variation and weight precision. 6T SRAM [1]–[3] provides the smallest cell area for CIM, but cell stability limits the number of activated cells, resulting in low parallelization. 10T and twin-8T [4]–[5] isolate the read/write paths for noise margin improvement, however both require special design of the bit cell using logic layout rules, resulting in over a 2x area overhead compared to foundry yield-optimized 6T SRAMs. Furthermore, single-bit precision of weights, in prior work [1]–[4], cannot meet the requirement for high-precision operations and scalability for large neural networks.