Mixed-signal analog-digital circuits design on the pre-diffused digital array using trapezoidal association of transistors

The mixed-signal and analog design on a pre-diffused array is a challenging task, given that the digital array is a linear matrix arrangement of minimum-length transistors. To surmount this drawback a specific discipline for designing analog circuits over such array is required. An important novel technique proposed is the use of TAT (Trapezoidal Associations of Transistors) composite transistors on the semi-custom Sea-Of-Transistors (SOT) array. The analysis and advantages of TAT arrangement are extensively analyzed and demonstrated, with simulation and measurement comparisons to equivalent single transistors. Basic analog cells were also designed as well in full-custom and TAT versions in 1.0mm and 0.5mm digital CMOS technologies. Most of the circuits were prototyped in full-custom and TAT-based on pre-diffused SOT arrays. An innovative demonstration of the TAT technique is shown with the design and implementation of a mixed-signal analog system, i. e., a fully differential 2nd order Sigma-Delta Analog-to-Digital (A/D) modulator, fabricated in both full-custom and SOT array methodologies in 0.5mm CMOS technology from MOSIS foundry. Three test-chips were designed and fabricated in 0.5mm. Two of them are IC chips containing the full-custom and SOT array versions of a 2nd-Order Sigma-Delta A/D modulator. The third IC contains a transistors-structure (TAT and single) and analog cells placed side-by-side, block components (Comparator and Folded-cascode OTA) of the Sigma-Delta modulator.

A Modular and digitally programmable interface based on band-pass sigma-delta modulator for mixed-signal systems-on-chip

The focus of this thesis is to discuss the development and modeling of an interface architecture to be employed for interfacing analog signals in mixed-signal SOC. We claim that the approach that is going to be presented is able to achieve wide frequency range, and covers a large range of applications with constant performance, allied to digital configuration compatibility. Our primary assumptions are to use a fixed analog block and to promote application configurability in the digital domain, which leads to a mixed-signal interface. The use of a fixed analog block avoids the performance loss common to configurable analog blocks. The usage of configurability on the digital domain makes possible the use of all existing tools for high level design, simulation and synthesis to implement the target application, with very good performance prediction. The proposed approach utilizes the concept of frequency translation (mixing) of the input signal followed by its conversion to the ΣΔ domain, which makes possible the use of a fairly constant analog block, and also, a uniform treatment of input signal from DC to high frequencies. The programmability is performed in the ΣΔ digital domain where performance can be closely achieved according to application specification. The interface performance theoretical and simulation model are developed for design space exploration and for physical design support. Two prototypes are built and characterized to validate the proposed model and to implement some application examples. The usage of this interface as a multi-band parametric ADC and as a two channels analog multiplier and adder are shown. The multi-channel analog interface architecture is also presented. The characterization measurements support the main advantages of the approach proposed.

Teste da rede de interconexões de field programmable analog arrays

Os dispositivos analógicos programáveis (FPAAs, do inglês, Field Programmable Analog Arrays), apesar de ainda não terem a mesma popularidade de seus pares digitais (FPGAs, do inglês, Field Programmable Gate Arrays), possuem uma gama de aplicações bastante ampla, que vai desde o condicionamento de sinais em sistemas de instrumentação, até o processamento de sinais de radiofreqüência (RF) em telecomunicações. Porém, ao mesmo tempo em que os FPAAs trouxeram um impressionante ganho na agilidade de concepção de circuitos analógicos, também trouxeram um conjunto de novos problemas relativos ao teste deste tipo de dispositivo. Os FPAAs podem ser divididos em duas partes fundamentais: seus blocos programáveis básicos (CABs, do inglês, Configurable Analog Blocks) e sua rede de interconexões. A rede de interconexões, por sua vez, pode ser dividida em duas partes: interconexões internas (locais e globais entre CABs) e interconexões externas (envolvendo células de I/O). Todas estas partes apresentam características estruturais e funcionais distintas, de forma que devem ser testadas separadamente, pois necessitam que se considerem modelos de falhas, configurações e estímulos de teste específicos para assegurar uma boa taxa de detecção de defeitos. Como trabalhos anteriores já estudaram o teste dos CABs, o foco desta dissertação está direcionado ao desenvolvimento de metodologias que se propõem a testar a rede de interconexões de FPAAs. Apesar das várias diferenças entre as redes de interconexões de FPGAs e FPAAs, muitas também são as semelhanças entre elas, sendo, portanto, indiscutível que o ponto de partida deste trabalho tenha que ser o estudo das muitas técnicas propostas para o teste de interconexões em FPGAs, para posterior adaptação ao caso dos FPAAs. Além disto, embora o seu foco não recaia sobre o teste de CABs, pretende-se utilizá-los como recursos internos do dispositivo passíveis de gerar sinais e analisar respostas de teste, propondo uma abordagem de auto-teste integrado de interconexões que reduza o custo relativo ao equipamento externo de teste. Eventualmente, estes mesmos recursos poderão também ser utilizados para diagnóstico das partes defeituosas. Neste trabalho, utiliza-se como veículo de experimentação um dispositivo específico (Anadigm AN10E40), mas pretende-se que as metodologias de teste propostas sejam abrangentes e possam ser facilmente adaptadas a outros FPAAs comerciais que apresentem redes de interconexão semelhantes.

Citizens and the future of multilateralism in a polycentric world at 2030: the perspectives of emerging countries for the trading system: the impasse of WTO, the trends of mega agreements, the logic of value chains and the advent of consumers concerns on international trade

A new paradigm is modeling the World: evolutionary innovations in all fronts, new information technologies, huge mobility of capital, use of risky financial tools, globalization of production, new emerging powers and the impact of consumer concerns on governmental policies. These phenomena are shaping the World and forcing the advent of a new World Order in the Multilateral Monetary, Financial, and Trading System. The effects of this new paradigm are also transforming global governance. The political and economic orders established after the World War and centered on the multilateral model of UN, IMF, World Bank, and the GATT, leaded by the developed countries, are facing significant challenges. The rise of China and emerging countries shifted the old model to a polycentric World, where the governance of these organizations are threatened by emerging countries demanding a bigger participation in the role and decision boards of these international bodies. As a consequence, multilateralism is being confronted by polycentrism. Negotiations for a more representative voting process and the pressure for new rules to cope with the new demands are paralyzing important decisions. This scenario is affecting seriously not only the Monetary and Financial Systems but also the Multilateral Trading System. International trade is facing some significant challenges: a serious deadlock to conclude the last round of the multilateral negotiation at the WTO, the fragmentation of trade rules by the multiplication of preferential and mega agreements, the arrival of a new model of global production and trade leaded by global value chains that is threatening the old trade order, and the imposition of new sets of regulations by private bodies commanded by transnationals to support global value chains and non-governmental organizations to reflect the concerns of consumers in the North based on their precautionary attitude about sustainability of products made in the World. The lack of any multilateral order in this new regulation is creating a big cacophony of rules and developing a new regulatory war of the Global North against the Global South. The objective of this paper is to explore how these challenges are affecting the Tradinge System and how it can evolve to manage these new trends.

Lula and Brazil: investors twisted logic

Investors were wrong to believe in change for the better; Brazil is stuck for at least two years