Algorithms for the scaling toward nanometer VLSI physical synthesis

Along the history of Very Large Scale Integration (VLSI), we have successfully scaled down the size of transistors, scaled up the speed of integrated circuits (IC) and the number of transistors in a chip - these are just a few examples of our achievement in VLSI scaling. It is projected to enter the nanometer (timing estimation and buffer planning for global routing and other early stages such as floorplanning. A novel path based buffer insertion scheme is also included, which can overcome the weakness of the net based approaches. Part-2 Circuit clustering techniques with the application in Field-Programmable Gate Array (FPGA) technology mapping The problem of timing driven n-way circuit partitioning with application to FPGA technology mapping is studied and a hierarchical clustering approach is presented for the latest multi-level FPGA architectures. Moreover, a more general delay model is included in order to accurately characterize the delay behavior of the clusters and circuit elements

Novel linear and nonlinear optical signal processing for ultra-high bandwidth communications

The thesis is articulated around the theme of ultra-wide bandwidth single channel signals. It focuses on the two main topics of transmission and processing of information by techniques compatible with high baudrates. The processing schemes introduced combine new linear and nonlinear optical platforms such as Fourier-domain programmable optical processors and chalcogenide chip waveguides, as well as the concept of neural network. Transmission of data is considered in the context of medium distance links of Optical Time Division Multiplexed (OTDM) data subject to environmental fluctuations. We experimentally demonstrate simultaneous compensation of differential group delay and multiple orders of dispersion at symbol rates of 640 Gbaud and 1.28 Tbaud. Signal processing at high bandwidth is envisaged both in the case of elementary post-transmission analog error mitigation and in the broader field of optical computing for high level operations (“optical processor”). A key innovation is the introduction of a novel four-wave mixing scheme implementing a dot-product operation between wavelength multiplexed channels. In particular, it is demonstrated for low-latency hash-key based all-optical error detection in links encoded with advanced modulation formats. Finally, the work presents groundbreaking concepts for compact implementation of an optical neural network as a programmable multi-purpose processor. The experimental architecture can implement neural networks with several nodes on a single optical nonlinear transfer function implementing functions such as analog-to-digital conversion. The particularity of the thesis is the new approaches to optical signal processing that potentially enable high level operations using simple optical hardware and limited cascading of components

Some Applications of the Weighted Combinatorial Laplacian

The weighted combinatorial Laplacian of a graph is a symmetric matrix which is the discrete analogue of the Laplacian operator. In this thesis, we will study a new application of this matrix to matching theory yielding a new characterization of factor-criticality in graphs and matroids. Other applications are from the area of the physical design of very large scale integrated circuits. The placement of the gates includes the minimization of a quadratic form given by a weighted Laplacian. A method based on the dual constrained subgradient method is proposed to solve the simultaneous placement and gate-sizing problem. A crucial step of this method is the projection to the flow space of an associated graph, which can be performed by minimizing a quadratic form given by the unweighted combinatorial Laplacian.Andwendungen der gewichteten kombinatorischen Laplace-Matrix Die gewichtete kombinatorische Laplace-Matrix ist das diskrete Analogon des Laplace-Operators. In dieser Arbeit stellen wir eine neuartige Charakterisierung von Faktor-Kritikalität von Graphen und Matroiden mit Hilfe dieser Matrix vor. Wir untersuchen andere Anwendungen im Bereich des Entwurfs von höchstintegrierten Schaltkreisen. Die Platzierung basiert auf der Minimierung einer quadratischen Form, die durch eine gewichtete kombinatorische Laplace-Matrix gegeben ist. Wir präsentieren einen Algorithmus für das allgemeine simultane Platzierungs- und Gattergrößen-Optimierungsproblem, der auf der dualen Subgradientenmethode basiert. Ein wichtiger Bestandteil dieses Verfahrens ist eine Projektion auf den Flussraum eines assoziierten Graphen, die als die Minimierung einer durch die Laplace-Matrix gegebenen quadratischen Form aufgefasst werden kann

Modeling EMI Resulting from a Signal Via Transition Through Power/Ground Layers

Signal transitioning through layers on vias are very common in multi-layer printed circuit board (PCB) design. For a signal via transitioning through the internal power and ground planes, the return current must switch from one reference plane to another reference plane. The discontinuity of the return current at the via excites the power and ground planes, and results in noise on the power bus that can lead to signal integrity, as well as EMI problems. Numerical methods, such as the finite-difference time-domain (FDTD), Moment of Methods (MoM), and partial element equivalent circuit (PEEC) method, were employed herein to study this problem. The modeled results are supported by measurements. In addition, a common EMI mitigation approach of adding a decoupling capacitor was investigated with the FDTD method

Design, scale-up and characterization of the data acquisition system for the ANAIS dark matter experiment

El proyecto ANAIS, iniciado en los noventa, se ha dedicado a desarrollar un experimento de materia oscura con ioduro de sodio en el Laboratorio Subterráneo de Canfranc (LSC) y podría confirmar el resultado positivo de DAMA/LIBRA usando la misma técnica y el mismo material blanco. Un experimento de estas características posee unos requisitos muy estrictos para tener sensibilidad suficiente a la modulación anual: tener el menor fondo radioactivo posible en la zona de interés, poseer un umbral energético muy bajo y tener suficiente masa. Además de estos requisitos fundamentales es necesaria una muy buena estabilidad en la adquisición de datos y un buen control de los parámetros ambientales para evitar que posibles efectos sistemáticos puedan ser tomados por modulación anual de materia oscura. El experimento ANAIS constará de más de cien kilogramos de ioduro de sodio ultrapuro en proceso de fabricación y que serán instalados en los próximos meses en el LSC. Esta tesis ha estado enfocada al diseño, implementación y caracterización de un sistema de adquisición de datos adecuado para el experimento ANAIS teniendo en cuenta los requisitos antes mencionados. Se han estudiado los fotomultiplicadores (PMTs) elegidos para la detección de la luz del centelleo del ioduro de sodio. Además se han desarrollado los algoritmos y protocolos necesarios para hacer el control de calidad de todas la unidades. Se ha descrito el diseño de la electrónica necesaria para la adquisición de datos de los módulos de ioduro y los centelladores plásticos usados como detector de muones junto con el software de adquisición y de análisis de datos. También se ha medido la recogida de luz de tres módulos de Alpha Spectra, los dos primeros de que constó el prototipo ANAIS-25 y un tercero que unido a los dos anteriores formaron ANAIS-37. Por último, se ha hecho un estudio de la estabilidad de los parámetros ambientales y de parámetros cruciales para la adquisición de datos.The ANAIS project has been a long time effort devoted to carry out an experiment to detect dark matter annual modulation with very low background NaI(Tl) detectors. This experiment could confirm the DAMA/LIBRA positive signal with the same target and technique. Such an experiment has a very stringent requirements in order to have enough sensitivity to an annual modulation at very low energy. These requirements are: very low energy threshold, a background as low as possible in the region of interest and a high enough target mass. In addition to these fundamental requirements, very good stability and control of environmental parameters have to be accomplished in order to avoid systematic effects to mimic the effect of the annual modulation. An experiment of more than one hundred kilograms of ultrapure NaI(Tl) has been conceived and it is being commissioned at the Canfranc Underground Laboratory (LSC). This work was devoted to the design, implementation and characterization of a data acquisition system suitable for the ANAIS experiment, having in mind the previously mentioned requirements. It has described the Photomultiplier Tubes (PMTs) used by the ANAIS modules and the algorithms and protocol developed in order to pass quality tests to all units. It has presented the design and implementation of the electronic front-end for the ANAIS modules and muon tagging system along with the data acquisition software. The analysis software was adapted from the software of the previous prototypes to allow easy scale-up to the full experiment. Finally, the test of the optical performance of the Alpha Spectra modules and the tests of data acquisition and monitoring of environmental parameters were performed

An integrated placement and routing approach

As the feature size continues scaling down, interconnects become the major contributor of signal delay. Since interconnects are mainly determined by placement and routing, these two stages play key roles to achieve high performance. Historically, they are divided into two separate stages to make the problem tractable. Therefore, the routing information is not available during the placement process. Net models such as HPWL, are employed to approximate the routing to simplify the placement problem. However, the good placement in terms of these objectives may not be routable at all in the routing stage because different objectives are optimized in placement and routing stages. This inconsistancy makes the results obtained by the two-step optimization method far from optimal;In order to achieve high-quality placement solution and ensure the following routing, we propose an integrated placement and routing approach. In this approach, we integrate placement and routing into the same framework so that the objective optimized in placement is the same as that in routing. Since both placement and routing are very hard problems (NP-hard), we need to have very efficient algorithms so that integrating them together will not lead to intractable complexity;In this dissertation, we first develop a highly efficient placer - FastPlace 3.0 for large-scale mixed-size placement problem. Then, an efficient and effective detailed placer - FastDP is proposed to improve global placement by moving standard cells in designs. For high-degree nets in designs, we propose a novel performance-driven topology design algorithm to generate good topologies to achieve very strict timing requirement. In the routing phase, we develop two global routers, FastRoute and FastRoute 2.0. Compared to traditional global routers, they can generate better solutions and are two orders of magnitude faster. Finally, based on these efficient and high-quality placement and routing algorithms, we propose a new flow which integrates placement and routing together closely. In this flow, global routing is extensively applied to obtain the interconnect information and direct the placement process. In this way, we can get very good placement solutions with guaranteed routability

A GridPix TPC readout for the ILD experiment at the future International Linear Collider

In the quest for a more complete theory of nature, the precise investigation of the Higgs boson at a future electron positron collider has the highest priority. The best tracking performance for a TPC at the proposed International Linear Collider is offered by a TPC with a GridPix readout. The viability of a GridPix TPC readout has been demonstrated in the two detector tests described in this thesis, and the expected performance is established in a comprehensive simulation. In conclusion, the GridPix has a lot of potential for experiments at the next generation of high-energy electron positron colliders