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Circuit Timing and Leakage Analysis in the Presence of Variability

Driven by the need for faster devices and higher transistor densities, technology trends have pushed transistor dimensions into the deep sub-micron regime. This continued scaling, however, has led to many challenges facing digital integrated circuits today. One important challenge is the increased variations in the underlying process and environmental parameters, and the significant impact of this variability on circuit timing and leakage power, making it increasingly difficult to design circuits that achieve a required specification. Given these challenges, there is a need for computer-aided design (CAD) techniques that can predict and analyze circuit performance (timing and leakage) accurately and efficiently in the presence of variability. This thesis presents new techniques for variation-aware timing and leakage analysis that address different aspects of the problem.


First, on the timing front, a pre-placement statistical static timing analysis technique is presented. This technique can be applied at an early stage of design, when within-die correlations are still unknown. Next, a general parameterized static timing analysis framework is proposed, which supports a general class of nonlinear delay models and handles both random (process) parameters with arbitrary distributions and non-random (environmental) parameters. Following this, a parameterized static timing analysis technique is presented, which can capture circuit delay exactly at any point in the parameter space. This is enabled by identifying all potentially critical paths in the circuit through novel and efficient pruning algorithms that improve on the state of art both in theoretical complexity and runtime. Also on the timing front, a novel distance-based metric for robustness is proposed. This metric can be used to quantify the susceptibility of parameterized timing quantities to failure, thus enabling designers to fix the nodes with smallest robustness values in order to improve the overall design robustness.


Finally, on the leakage front, a statistical technique for early-mode and late-mode leakage estimation is presented. The novelty lies in the random gate concept, which allows for efficient and accurate full-chip leakage estimation. In its simplest form, the leakage estimation reduces to finding the area under a scaled version of the within-die channel length auto-correlation function, which can be done in constant time.

Identiferoai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/26186
Date15 February 2011
CreatorsHeloue, Khaled R.
ContributorsNajm, Farid N.
Source SetsUniversity of Toronto
Languageen_ca
Detected LanguageEnglish
TypeThesis

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