A 5T0C eDRAM-Based Content Addressable Memory for High-Density Searching and Logic-in-Memory
Jincheng Wang, Yuhao Shu, Lintao Lan, Yifei Li, Bin Ning, Yuxin Zhou, Hongtu Zhang, Yajun Ha · IEEE Transactions on Very Large Scale Integration (VLSI) Systems · 2025
With the development of big data, there is an increasing demand for high-density searching, where content-addressable memory (CAM) presents an attractive solution for its ability to perform parallel searches. However, this goal is constrained by the difficulty of further reducing the area of SRAM cells, which is commonly used in traditional CAM implementations. To address this issue, we propose a novel CAM with a compact five-transistor-zero-capacitor (5T0C)-embedded dynamic random access memory (eDRAM) for high-density searching and logic-in-memory applications. First, we propose the 5T0C eDRAM gain cell featuring a 3T0C write port and a decoupled read port of 2T to achieve data storage and searching operations. Second, we present a reconfigurable sense amplifier (RSA) design with two different reference voltages to optimize the area overhead of peripheral circuits and support logic operations. Moreover, the 5T0C eDRAM-based CAM can be employed to achieve high-density searching and logic operations. We have validated the eDRAM-based CAM array in the 40-nm CMOS process. The postlayout simulation results show that our design achieves over 15% higher memory density compared to the state-of-the-art 6T SRAM. Additionally, it supports a maximum frequency of 637 and 658 MHz for binary CAM (BCAM) searching and logic operations, while consuming 0.91 and 27.47 fJ/bit at 1.1 V, respectively.