319 research outputs found

    Layout optimizations of operational amplifier in deep submicron

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    Abstract—Operational amplifies (op amps) are an integral part of many analog and mixed-signal systems. Op amps with vastly different levels of complexity are used to realize functions ranging from DC bias generation to high-speed amplification or filtering. The design of op amps continues to pose a challenge as the supply voltage and transistor channel lengths scale down with each generation of CMOS technologies. The thesis deals with the analysis, design and layout optimization of CMOS op amps in deep Submicron (DSM) from a study case. Finally, layout optimizations of op amps will be given, in which propose optimization techniques to mitigate these DSM effects in the place-and-route stage of VLSI physical design

    Equivalent Waveform Propagation for Static Timing Analysis

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    Evaluation And Modeling Of High-Voltage Cable Insulation Using A High-Voltage Impulse

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    Failure of underground cable on San Diego Gas & Electric\u27s electric underground distribution system is an ever increasing problem. While there are a great number of cable diagnostic techniques available, none lend themselves to both an averaged and location specific, on-line implementation. This dissertation demonstrates the development of an on-line suitable technique that utilizes transients and Fast Fourier Transforms to determine a cable section?s impedance magnitude and phase angle as a function of frequency. Simultaneously a theoretical model was developed to simulate various scenarios that an in-service cable might experience. Significant effort was expended developing and optimizing the measurement and data analysis technique. This includes a statistical approach for comparing performance of different cable samples. Both the preliminary and final tests demonstrated the superiority of the frequency domain analysis over comparisons in the time domain. With the effort to date, there appears to be three distinct results: good cable, degraded cable and damaged cable. These differences are statistically significant at the 95% confidence level. Additionally, there appears to be good agreement between the theoretical model and actual test results. Consequently, this measurement methodology continues to hold promise for future practical development

    Investigation of Interconnect and Device Designs for Emerging Post-MOSFET and Beyond Silicon Technologies

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    Title from PDF of title page viewed May 31, 2017Dissertation advisor: Masud H. ChowdhuryVitaIncludes bibliographical references (pages 94-108)Thesis (Ph.D.)--School of Computing and Engineering and Department of Physics and Astronomy. University of Missouri--Kansas City, 2016The integrated circuit industry has been pursuing Moore’s curve down to deep nanoscale dimensions that would lead to the anticipated delivery of 100 billion transistors on a 300 mm² die operating below 1V supply in the next 5-10 years. However, the grand challenge is to reliably and efficiently take the full advantage of the unprecedented computing power offered by the billions of nanoscale transistors on a single chip. To mitigate this challenge, the limitations of both the interconnecting wires and semiconductor devices in integrated circuits have to be addressed. At the interconnect level, the major challenge in current high density integrated circuit is the electromagnetic and electrostatic impacts in the signal carrying lines. Addressing these problems require better analysis of interconnect resistance, inductance, and capacitance. Therefore, this dissertation has proposed a new delay model and analyzed the time-domain output response of complex poles, real poles, and double poles for resistance-inductance capacitance interconnect network based on a second order approximate transfer function. Both analytical models and simulation results show that the real poles model is much faster than the complex poles model, and achieves significantly higher accuracy in order to characterize the overshoot and undershoot of the output responses. On the other hand, the semiconductor industry is anticipating that within a decade silicon devices will be unable to meet the demands at nanoscale due to dimension and material scaling. Recently, molybdenum disulfide (MoS₂) has emerged as a new super material to replace silicon in future semiconductor devices. Besides, conventional field effect transistor technology is also reaching its thermodynamic limit. Breaking this thermal and physical limit requires adoption of new devices based on tunneling mechanism. Keeping the above mentioned trends, this dissertation also proposed a multilayer MoS₂ channel-based tunneling transistor and identifies the fundamental parameters and design specifications that need to be optimized in order to achieve higher ON-currents. A simple analytical model of the proposed device is derived by solving the time-independent Schrodinger equation. It is analytically proven that the proposed device can offer an ON-current of 80 A/m, a subthreshold swing (S) of 9.12 mV/decade, and a / ratio of 10¹².Introduction -- Previous models on interconnect designs -- Proposed delay model for interconnect design -- Investigation of tunneling for field effect transistor -- Study of molybdenum disulfide for FET applications -- Proposed molybdenum disulfide based tunnel transistor -- Conclusion -- Appendix A. Derivation of time delay model -- Appendix B. Derivation of tunneling current model Appendix C. Derivation of subthreshold swing mode

    Structure-Function Analysis of Motor Proteins: Insights from Conventional and Unconventional Myosins

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    University of Minnesota Ph.D. dissertation.December 2016. Major: Biochemistry, Molecular Bio, and Biophysics. Advisors: Margaret Titus, David Thomas. 1 computer file (PDF); xv, 171 pages.Myosin motor proteins play fundamental roles in a multitude of cellular processes. Myosin generates force on cytoskeletal actin filaments to control cell shape, most dramatically during cytokinesis, and has a conserved role in defining cell polarity. Myosin contracts the actin cytoskeleton, ensuring prompt turnover of cellular adhesion sites, retracting the cell body during migration and development, and contracting muscle among diverse other functions. How myosins work, and why force generation is essential for their function, is in many cases an open question. Chapter 2 presents a structure-function analysis of the amoebozoan myosin 7 (DdMyo7) in live Dictyostelium discoideum cells. DdMyo7 bears structural resemblance to human Myosin 7 (a protein involved in maintenance of the retina, stereocilia of the ear, and gut microvilli) but has functional similarity to human Myosin 10, a regulator of cell adhesion that is also essential in formation of actin-based structures called filopodia. Phylogenetic analysis of these related proteins shows that DdMyo7 is not directly related to any human myosin but rather represents a molecular ancestor of several vertebrate myosins (Myo7, Myo10 and Myo15). Functional analysis focused on rescue of myo7– cells. The two MyTH4-FERM domains were fully redundant in rescuing formation of filopodia. A conserved Myo7 regulatory motif in the C-terminal FERM domain was found to stimulate filopodia formation when mutated, establishing DdMyo7 as a filopodial motor with features of Myo7 and Myo10. A molecular chimera of DdMyo7 motor/lever arm region fused to the MF domain of human Myo10 partially rescued filopodia formation, suggesting the MF domain plays a similar role in filopodia in divergent organisms. Structural information must be combined with physiological data to understand the mechanism of myosin motor function. Structural studies have long focused on conventional myosin 2 as a model due to ease of protein expression and purification. This approach has yielded considerable data regarding the static structures and in vitro kinetics of the myosin mechanochemical cycle; however, high-resolution methods to observe the dynamics of myosin activation in cells have been lacking. Chapter 4 introduces methods and instrumentation for rapid, precise measurement of fluorescence lifetime. This is a necessary step toward Myo2-based live cell FRET sensors described in Chapter 5. Implications of this work for future studies of myosin physiological function are discussed in Chapter 6

    Custom Integrated Circuits

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    Contains table of contents for Part III, table of contents for Section 1 and reports on eleven research projects.IBM CorporationMIT School of EngineeringNational Science Foundation Grant MIP 94-23221Defense Advanced Research Projects Agency/U.S. Army Intelligence Center Contract DABT63-94-C-0053Mitsubishi CorporationNational Science Foundation Young Investigator Award Fellowship MIP 92-58376Joint Industry Program on Offshore Structure AnalysisAnalog DevicesDefense Advanced Research Projects AgencyCadence Design SystemsMAFET ConsortiumConsortium for Superconducting ElectronicsNational Defense Science and Engineering Graduate FellowshipDigital Equipment CorporationMIT Lincoln LaboratorySemiconductor Research CorporationMultiuniversity Research IntiativeNational Science Foundatio
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