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Description
A fully automated logic design methodology for radiation hardened by design (RHBD) high speed logic using fine grained triple modular redundancy (TMR) is presented. The hardening techniques used in the cell library are described and evaluated, with a focus on both layout techniques that mitigate total ionizing dose (TID) and latchup issues and flip-flop designs that mitigate single event transient (SET) and single event upset (SEU) issues. The base TMR self-correcting master-slave flip-flop is described and compared to more traditional hardening techniques. Additional refinements are presented, including testability features that disable the self-correction to allow detection of manufacturing defects. The circuit approach is validated for hardness using both heavy ion and proton broad beam testing. For synthesis and auto place and route, the methodology and circuits leverage commercial logic design automation tools. These tools are glued together with custom CAD tools designed to enable easy conversion of standard single redundant hardware description language (HDL) files into hardened TMR circuitry. The flow allows hardening of any synthesizable logic at clock frequencies comparable to unhardened designs and supports standard low-power techniques, e.g. clock gating and supply voltage scaling.
ContributorsHindman, Nathan (Author) / Clark, Lawrence T (Thesis advisor) / Holbert, Keith E. (Committee member) / Barnaby, Hugh (Committee member) / Allee, David (Committee member) / Arizona State University (Publisher)
Created2012
Description
Understanding charge transport in single molecules covalently bonded to electrodes is a fundamental goal in the field of molecular electronics. In the past decade, it has become possible to measure charge transport on the single-molecule level using the STM break junction method. Measurements on the single-molecule level shed light on charge transport phenomena which would otherwise be obfuscated by ensemble measurements of groups of molecules. This thesis will discuss three projects carried out using STM break junction. In the first project, the transition between two different charge transport mechanisms is reported in a set of molecular wires. The shortest wires show highly length dependent and temperature invariant conductance behavior, whereas the longer wires show weakly length dependent and temperature dependent behavior. This trend is consistent with a model whereby conduction occurs by coherent tunneling in the shortest wires and by incoherent hopping in the longer wires. Measurements are supported with calculations and the evolution of the molecular junction during the pulling process is investigated. The second project reports controlling the formation of single-molecule junctions by means of electrochemically reducing two axial-diazonium terminal groups on a molecule, thereby producing direct Au-C covalent bonds in-situ between the molecule and gold electrodes. Step length analysis shows that the molecular junction is significantly more stable, and can be pulled over a longer distance than a comparable junction created with amine anchoring bonds. The stability of the junction is explained by the calculated lower binding energy associated with the direct Au-C bond compared with the Au-N bond. Finally, the third project investigates the role that molecular conformation plays in the conductance of oligothiophene single-molecule junctions. Ethyl substituted oligothiophenes were measured and found to exhibit temperature dependent conductance and transition voltage for molecules with between two and six repeat units. While the molecule with only one repeat unit shows temperature invariant behavior. Density functional theory calculations show that at higher temperatures the oligomers with multiple repeat units assume a more planar conformation, which increases the conjugation length and decreases the effective energy barrier of the junction.
ContributorsHines, Thomas (Author) / Tao, Nongjian (Thesis advisor) / Li, Jian (Thesis advisor) / Mujica, Vladimiro (Committee member) / Allee, David (Committee member) / Arizona State University (Publisher)
Created2013
Description
Analysing and measuring of biological or biochemical processes are of utmost importance for medical, biological and biotechnological applications. Point of care diagnostic system, composing of biosensors, have promising applications for providing cheap, accurate and portable diagnosis. Owing to these expanding medical applications and advances made by semiconductor industry biosensors have seen a tremendous growth in the past few decades. Also emergence of microfluidics and non-invasive biosensing applications are other marker propellers. Analyzing biological signals using transducers is difficult due to the challenges in interfacing an electronic system to the biological environment. Detection limit, detection time, dynamic range, specificity to the analyte, sensitivity and reliability of these devices are some of the challenges in developing and integrating these devices. Significant amount of research in the field of biosensors has been focused on improving the design, fabrication process and their integration with microfluidics to address these challenges. This work presents new techniques, design and systems to improve the interface between the electronic system and the biological environment. This dissertation uses CMOS circuit design to improve the reliability of these devices. Also this work addresses the challenges in designing the electronic system used for processing the output of the transducer, which converts biological signal into electronic signal.
ContributorsShah, Sahil S (Author) / Christen, Jennifer B (Thesis advisor) / Allee, David (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2014
Description
The geometric growth in the integrated circuit technology due to transistor scaling also with system-on-chip design strategy, the complexity of the integrated circuit has increased manifold. Short time to market with high reliability and performance is one of the most competitive challenges. Both custom and ASIC design methodologies have evolved over the time to cope with this but the high manual labor in custom and statistic design in ASIC are still causes of concern. This work proposes a new circuit design strategy that focuses mostly on arrayed structures like TLB, RF, Cache, IPCAM etc. that reduces the manual effort to a great extent and also makes the design regular, repetitive still achieving high performance. The method proposes making the complete design custom schematic but using the standard cells. This requires adding some custom cells to the already exhaustive library to optimize the design for performance. Once schematic is finalized, the designer places these standard cells in a spreadsheet, placing closely the cells in the critical paths. A Perl script then generates Cadence Encounter compatible placement file. The design is then routed in Encounter. Since designer is the best judge of the circuit architecture, placement by the designer will allow achieve most optimal design. Several designs like IPCAM, issue logic, TLB, RF and Cache designs were carried out and the performance were compared against the fully custom and ASIC flow. The TLB, RF and Cache were the part of the HEMES microprocessor.
ContributorsMaurya, Satendra Kumar (Author) / Clark, Lawrence T (Thesis advisor) / Holbert, Keith E. (Committee member) / Vrudhula, Sarma (Committee member) / Allee, David (Committee member) / Arizona State University (Publisher)
Created2012
Description
The goal of this project was to explore biomimetics by creating a jellyfish flying device that uses propulsion of air to levitate while utilizing electromyography signals and infrared signals as mechanisms to control the device. Completing this project would require knowledge of biological signals, electrical circuits, computer programming, and physics to accomplish. An EMG sensor was used to obtain processed electrical signals produced from the muscles in the forearm and was then utilized to control the actuation speed of the tentacles. An Arduino microprocessor was used to translate the EMG signals to infrared blinking sequences which would propagate commands through a constructed circuit shield to the infrared receiver on jellyfish. The receiver will then translate the received IR sequence into actions. Then the flying device must produce enough thrust to propel the body upwards. The application of biomimetics would best test my skills as an engineer as well as provide a method of applying what I have learned over the duration of my undergraduate career.
ContributorsTsui, Jessica W (Author) / Muthuswamy, Jitteran (Thesis director) / Blain Christen, Jennifer (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
This paper summarizes the [1] ideas behind, [2] needs, [3] development, and [4] testing of 3D-printed sensor-stents known as Stentzors. This sensor was successfully developed entirely from scratch, tested, and was found to have an output of 3.2*10-6 volts per RMS pressure in pascals. This paper also recommends further work to render the Stentzor deployable in live subjects, including [1] further design optimization, [2] electrical isolation, [3] wireless data transmission, and [4] testing for aneurysm prevention.
ContributorsMeidinger, Aaron Michael (Author) / LaBelle, Jeffrey (Thesis director) / Frakes, David (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
Description
Growing concern over health risks associated with environmental contaminants has prompted an increase in the search for effective detection methods. The available options provide acceptable sensitivity and specificity, but with high purchase and maintenance costs. Herein, a low-cost, portable environmental contaminant sensor was developed using electrochemical techniques and an efficient hydrogel capture mechanism. The sensor operates with high sensitivity and maintains specificity without the added requirement of extensive electrode modification. Rather, specificity is obtained by choosing specific potential regions in which individual contaminants show reduction or oxidation activity. A calibration curve was generated showing the utility of the sensor in detecting gas compounds reliably in reference to a current state of the art sensor. Reusability of the sensor was also demonstrated with a cyclic exposure test in which response reversibility was observed. As such, the investigated sensor shows great promise as a replacement technology in the current environmental contaminant detector industry.
ContributorsMarch, Michael Stephen (Author) / LaBelle, Jeffrey (Thesis director) / Caplan, Michael (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
Diabetes mellitus is a disease characterized by many chronic and acute conditions. With the prevalence and cost quickly increasing, we seek to improve on the current standard of care and create a rapid, label free sensor for glycated albumin (GA) index using electrochemical impedance spectroscopy (EIS). The antibody, anti-HA, was fixed to gold electrodes and a sine wave of sweeping frequencies was induced with a range of HA, GA, and GA with HA concentrations. Each frequency in the impedance sweep was analyzed for highest response and R-squared value. The frequency with both factors optimized is specific for both the antibody-antigen binding interactions with HA and GA and was determined to be 1476 Hz and 1.18 Hz respectively in purified solutions. The correlation slope between the impedance response and concentration for albumin (0 \u2014 5400 mg/dL of albumin) was determined to be 72.28 ohm/ln(mg/dL) with an R-square value of 0.89 with a 2.27 lower limit of detection. The correlation slope between the impedance response and concentration for glycated albumin (0 \u2014 108 mg/dL) was determined to be -876.96 ohm/ln(mg/dL) with an R-squared value of 0.70 with a 0.92 mg/dL lower limit of detection (LLD). The above data confirms that EIS offers a new method of GA detection by providing unique correlation with albumin as well as glycated albumin. The unique frequency response of GA and HA allows for modulation of alternating current signals so that several other markers important in the management of diabetes could be measured with a single sensor. Future work will be necessary to establish multimarker sensing on one electrode.
ContributorsEusebio, Francis Ang (Author) / LaBelle, Jeffrey (Thesis director) / Pizziconi, Vincent (Committee member) / Barrett, The Honors College (Contributor) / Harrington Bioengineering Program (Contributor)
Created2014-05
Description
This project examines the science of electric field sensing and completes experiments, gathering data to support its utility for various applications. The basic system consists of a transmitter, receiver, and lock-in amplifier. The primary goal of the study was to determine if such a system could detect a human disturbance, due to the capacitance of a human body, and such a thesis was supported. Much different results were obtained when a person disturbed the electric field transmitted by the system than when other types of objects, such as chairs and electronic devices, were placed in the field. In fact, there was a distinct difference between persons of varied sizes as well. This thesis goes through the basic design of the system and the process of experimental design for determining the capabilities of such an electric field sensing system.
ContributorsBranham, Breana Michelle (Author) / Allee, David (Thesis director) / Papandreou-Suppappola, Antonia (Committee member) / Phillips, Stephen (Committee member) / Barrett, The Honors College (Contributor) / Electrical Engineering Program (Contributor) / School of International Letters and Cultures (Contributor)
Created2013-05
Description
Radiation hardening by design (RHBD) has become a necessary practice when creating circuits to operate within radiated environments. While employing RHBD techniques has tradeoffs between size, speed and power, novel designs help to minimize these penalties. Space radiation is the primary source of radiation errors in circuits and two types of single event effects, single event upsets (SEU), and single event transients (SET) are increasingly becoming a concern. While numerous methods currently exist to nullify SEUs and SETs, special consideration to the techniques of temporal hardening and interlocking are explored in this thesis. Temporal hardening mitigates both SETs and SEUs by spacing critical nodes through the use of delay elements, thus allowing collected charge to be removed. Interlocking creates redundant nodes to rectify charge collection on one single node. This thesis presents an innovative, temporally hardened D flip-flop (TFF). The TFF physical design is laid out in the 130 nm TSMC process in the form of an interleaved multi-bit cell and the circuitry necessary for the flip-flop to be hardened against SETs and SEUs is analyzed with simulations verifying these claims. Comparisons are made to an unhardened D flip-flop through speed, size, and power consumption depicting how the RHBD technique used increases all three over an unhardened flip-flop. Finally, the blocks from both the hardened and the unhardened flip-flops being placed in Synthesis and auto-place and route (APR) design flows are compared through size and speed to show the effects of using the high density multi-bit layout. Finally, the TFF presented in this thesis is compared to two other flip-flops, the majority voter temporal/DICE flip-flop (MTDFF) and the C-element temporal/DICE flip-flop (CTDFF). These circuits are built on the same 130 nm TSMC process as the TFF and then analyzed by the same methods through speed, size, and power consumption and compared to the TFF and unhardened flip-flops. Simulations are completed on the MTDFF and CTDFF to show their strengths against D node SETs and SEUs as well as their weakness against CLK node SETs. Results show that the TFF is faster and harder than both the MTDFF and CTDFF.
ContributorsMatush, Bradley (Author) / Clark, Lawrence T (Thesis advisor) / Allee, David (Committee member) / Bakkaloglu, Bertan (Committee member) / Arizona State University (Publisher)
Created2010