Title
Variability modeling in near-threshold CMOS digital circuits
Abstract
Sub-threshold operation is an efficient solution for ultra low power applications. However, it is very sensitive to process variability which can impact the robustness and effective performance of the circuit. On the other hand, this sensitivity decreases toward near-threshold operation. In this paper, the impact of variability on sub-threshold and near-threshold circuit performance is investigated through analytical modeling and circuit simulation in a 65nm industrial low power CMOS process. It is shown that variability moves the effective minimum energy point toward the near-threshold region. Also, when variability is taken into account, a complete model including the region near-threshold (moderate inversion) is required to correctly model circuit performance around the minimum energy point. An analytical solution for the optimum supply voltage that minimizes the total energy per operation, while considering variability effects, is provided. Additionally, the resulting speed-consumption trade-off in a variability aware analysis of sub-threshold and near-threshold operation is presented. Graphical abstractDisplay Omitted HighlightsVariability is a strong limitation for sub and near-threshold digital CMOS.Variability moves the minimum energy point towards the near-threshold region.We propose a simple model for assessing the delay-energy trade-off with variability.The model is validated in a 32 bit adder and a 8 bit multiplier test cases.We derive an analytical solution of the VDD for minimum energy with variability.
Year
DOI
Venue
2015
10.1016/j.mejo.2015.10.001
Microelectronics Journal
Keywords
Field
DocType
Sub-threshold logic,Near-threshold operation,Variability,Modeling
32-bit,Adder,Computer science,Inversion (meteorology),Voltage,8-bit,Cmos digital circuits,Multiplier (economics),Robustness (computer science),Electronic engineering
Journal
Volume
Issue
ISSN
46
12
0026-2692
Citations 
PageRank 
References 
3
0.40
10
Authors
3
Name
Order
Citations
PageRank
Mariem Slimani1237.05
Fernando Silveira23616.18
Philippe Matherat3296.32