Correlation between static random access memory power-up state and transistor variation. (10th February 2017)

• Record Type: Journal Article
• Authors: Takeuchi, Kiyoshi; Mizutani, Tomoko; Saraya, Takuya; Shinohara, Hirofumi; Kobayashi, Masaharu; Hiramoto, Toshiro
• Is Part Of: Japanese journal of applied physics. Volume 56:Number 4(2017)Supplement
• Publication Date: 2017-02-10
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.56.04CD03
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: The correlation between the static random access memory (SRAM) power-up state (i.e., state 0 or 1 immediately after the power supply is turned on) and cell transistor variation is systematically studied by circuit simulations and mismatch space partitioning. It is revealed that, while both the mismatches of pFETs (pull-up) and nFETs (pull-down and access) contribute, their relative importance changes depending on the voltage ramping speed. The static retention noise margin well correlates with the power-up state only if the ramping speed is sufficiently low. Otherwise, pull-up transistor mismatch dominates the power-up state determination owing to the interference of capacitive current and asymmetrical capacitive coupling of the storage nodes to the ground and power supply.