An Offset-Tolerant Fast-Random-Read Current-Sampling-Based Sense Amplifier for Small-Cell-Current Nonvolatile Memory

作者：Chang Meng Fan^*; Shen Shin Jang; Liu Chia Chi; Wu Che Wei; Lin Yu Fan; King Ya Chin; Lin Chorng Jung; Liao Hung Jen; Chih Yu Der; Yamauchi Hiroyuki

来源：IEEE Journal of Solid-State Circuits, 2013, 48(3): 864-877.

DOI：10.1109/JSSC.2012.2235013

• Sense amplifier
• nonvolatile memory
• OTP
• current sampling
• offset tolerant

Decreasing read cell current (I-CELL) has become a major trend in nonvolatile memory (NVM). However, a reduced I-CELL leaves the operation of the sense amplifier (SAs) vulnerable to bitline (BL) level offset and SA input offset. Thus, small-I-CELL NVMs suffer from slow read speed or low read yield. In this study, we propose a new current-sampling-based SA (CSB-SA) to suppress the offset due to device mismatch, while maintaining tolerance for insufficient precharge time. These features enable CSB-SA to achieve a read speed 6.3x -8.1x faster than previous SAs, for sensing 100 nA I-CELLs on a 2K-cell bitline. We fabricated a CMOS-logic-compatible, 90 nm, 512 Kb OTP macro, using the CSB-SA. This OTP macro achieves a random access time of 26 ns for reading sub-200 nA I-CELL. Measurements confirm that this 90 nm CSB-SA is also capable of sub-100 nA sensing.

• 出版日期2013-3
• 单位中国科学院电工研究所; 清华大学