Reexamination of SRAM Cell Write Margin Definitions in View of Predicting the Distribution
Reexamination of SRAM Cell Write Margin Definitions in View of Predicting the Distribution
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DOI：
10.1109/tcsii.2011.2124531
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发表时间：
2011-04
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影响因子：
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通讯作者：
H. Makino;S. Nakata;Hirotsugu Suzuki;S. Mutoh;M. Miyama;T. Yoshimura;S. Iwade;Y. Matsuda
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文献类型：
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作者：
H. Makino;S. Nakata;Hirotsugu Suzuki;S. Mutoh;M. Miyama;T. Yoshimura;S. Iwade;Y. Matsuda
通过分析静态随机存取存储器（SRAM）单元写裕度（WM）对SRAM单元晶体管阈值电压（Vth）的依赖关系，重新审视了静态随机存取存储器（SRAM）单元写裕度（WM）的四种定义，以找到一种更好的定义。如果WM对Vth的微分系数在Vth变化的宽范围内是恒定的，则WM预期服从正态分布。这意味着写入良率可以通过少量的测量样本容易地预测。使用SPICE在45纳米技术，我们检查了定义具有Vth线性，以及给出一个准确的写入限制。通过Monte Carlo模拟验证了根据线性预测的分布。结果表明，Gierczynski提出的定义是预测分布和写入成品率的最合适的定义。
Four definitions of static random access memory (SRAM) cell write margins (WMs) were reexamined by analyzing the dependence of the WM on the SRAM cell transistor threshold voltages (Vth's) in order to find a preferable definition. The WM is expected to obey the normal distribution if the differential coefficients of the WM to Vth's are constant over a wide range of Vth variations. This means that the write yield can be easily predicted by a small number of measured samples. Using SPICE in 45-nm technology, we examined which definition had Vth linearity, as well as giving an accurate write limit. The distribution predicted from the linearity was verified by the Monte Carlo simulation. As a result, the definition proposed by Gierczynski was found to be the most suitable definition for predicting the distribution and the write yield.