TY - JOUR
T1 - Impact of process variation on self-reference sensing scheme and adaptive current modulation for robust STTRAM sensing
AU - Motaman, Seyedhamidreza
AU - Ghosh, Swaroop
AU - Kulkarni, Jaydeep
N1 - Funding Information:
This article is based on work supported by Semiconductor Research Corporation (#2727.001) and National Science Foundation (CNS-1441757). Authors’ addresses: S. Motaman and S. Ghosh, Computer Science and Engineering Department, Pennsylvania State University, University Park-Pennsylvania; emails: {sxm884, szg212}@psu.edu; J. Kulkarni, Intel Labs, Hillsboro, OR; email: [email protected]. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]. © 2017 ACM 1550-4832/2017/10-ART8 $15.00 https://doi.org/10.1145/3132577
PY - 2017/10
Y1 - 2017/10
N2 - Spin-Transfer-Torque RAM (STTRAM) is a promising technology for high-density on-chip cache due to low standby power and high speed. However, the process variation of the Magnetic Tunnel Junction (MTJ) and access transistor poses a serious challenge to sensing. Nondestructive sensing suffers from reference resistance variation, whereas destructive sensing suffers from failures due to unoptimized selection of data and reference currents. Furthermore, the sense speed is tightly coupled with the reference/data current requirement. In this work, we study the process variation effect on a self-reference sensing scheme to eliminate bit-to-bit process variation in MTJ resistance. Read current modulation is proposed to overcome the failures due to process variation. Simulation results reveal <0.01% failures at the cost of 9ns sense time and 190uW power consumption.
AB - Spin-Transfer-Torque RAM (STTRAM) is a promising technology for high-density on-chip cache due to low standby power and high speed. However, the process variation of the Magnetic Tunnel Junction (MTJ) and access transistor poses a serious challenge to sensing. Nondestructive sensing suffers from reference resistance variation, whereas destructive sensing suffers from failures due to unoptimized selection of data and reference currents. Furthermore, the sense speed is tightly coupled with the reference/data current requirement. In this work, we study the process variation effect on a self-reference sensing scheme to eliminate bit-to-bit process variation in MTJ resistance. Read current modulation is proposed to overcome the failures due to process variation. Simulation results reveal <0.01% failures at the cost of 9ns sense time and 190uW power consumption.
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U2 - 10.1145/3132577
DO - 10.1145/3132577
M3 - Article
AN - SCOPUS:85032806889
SN - 1550-4832
VL - 14
JO - ACM Journal on Emerging Technologies in Computing Systems
JF - ACM Journal on Emerging Technologies in Computing Systems
IS - 1
M1 - 8
ER -