A Multi-Functional 4T2R ReRAM Macro Enabling 2-Dimensional Access and Computing In-Memory

This paper presents a multi-functional resistive random access memory (ReRAM) macro using a novel 4T2R bit-cell. The proposed 4T2R ReRAM enables 2-dimensional (2-D) memory access, which offers significant latency and energy reductions for many applications such as matrix operations. Besides non-volatile storage, the proposed 4T2R ReRAM can support two types of computing in-memory operations: ternary content-addressable memory (TCAM) and logic in-memory (LIM). Evaluations on various matrix operations show that the proposed 4T2R ReRAM with 2-D access capability can reduce memory access latency and energy by up to 88% and 82%, respectively compared with conventional 1T1R ReRAM. For TCAM, the proposed 4T2R bit-cell takes a smaller area than SRAM-based TCAM cell, while achieves a comparable search speed. For LIM, we propose an optimized LIM full adder (LIM-FA) that improves the delay and the power by 3.2x and 1.6x, respectively compared with prior LIM-FAs.