A 1Mb 28nm STT-MRAM with 2.8ns Read Access Time at 1.2V VDD Using Single-Cap Offset-Cancelled Sense Amplifier and In-situ Self-Write-Termination

📋 论文概要

该论文提出了一种在28nm工艺下实现的1Mb STT-MRAM，通过采用单电容偏移抵消感测放大器，实现了2.8ns的快速读取访问时间，有效解决了传统STT-MRAM感测裕度小和参考电压随工艺变化漂移的问题。

💡 主要创新点

• 提出单电容偏移抵消感测放大器，提高了感测裕度并补偿了工艺偏差
• 通过In-situ参考电压跟踪机制，增强了读操作的可靠性

🏷 关键词

📄 原文摘要

spin-transfer-torque (STT) MRAM is a promising candidate for nextgeneration high-density embedded non-volatile memory [1-2]. However, 1T1R STT-MRAM suffers from limited sensing margin and high write power. As shown in Fig. 30.2.1(a), sense amplifier design is challenging due to the small difference (only 2×) between the high-resistance state (RAP) and the low-resistance state (RP), as well as RAP degradation with increasing temperature. Moreover, RP and RAP resistance distributions shift with process variation, requiring a read reference (Vref) that tracks process. To improve the sensing margin, several offset-cancellation methods have been reported to reduce sense amplifier mismatch [3]. However, these methods use multiple capacitors and hence incur significant area overheads.

👥 作者与机构

Qing Dong1,2, Zhehong Wang1, Jongyup Lim1, Yiqun Zhang1,

Yi-Chun Shih3, Yu-Der Chih3, Jonathan Chang3, David Blaauw1, Dennis Sylvester1 University of Michigan, Ann Arbor, MI; 2TSMC, San Jose, CA TSMC, Hsinchu, Taiwan 1 3 1T1R