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Superconductor electronics based on the Single Flux Quantum (SFQ) technology are considered a strong contender for the ‘beyond CMOS’ future of digital circuits because of the high speed and low power dissipation associated with them. In fact, digital operations beyond tens of GHz have been routinely demonstrated in the SFQ technology. These circuits have widespread applications such as high-speed analog-to-digital conversion, digital signal processing, high speed computing and in emerging topics such as control circuitry for superconducting quantum computing. Rapid Single Flux Quantum (RSFQ) circuits have emerged as a promising candidate within the SFQ technology, with information encoded in picosecond wide, milli-volt voltage pulses. As is the case with any integrated circuit technology, scalability of RSFQ circuits is essential to realizing their applications. These circuits, based on the Josephson junction, require a DC bias current for the correct operation. The DC bias current requirement increases with circuit complexity, and this has multiple implications on circuit operation. Large currents produce magnetic fields that can interfere with logic operation. Furthermore, the heat load delivered to the superconducting chip also increases with current which could result in the circuit becoming ‘normal’ and not superconducting. These problems make reduction of the bias current necessary. Serial Biasing (SB) is a bias current reduction technique, that has been proposed in the past. In this technique, a digital circuit is partitioned into multiple identical islands and bias current is provided to each island in a serial manner. While this scheme is promising, there are multiple challenges such as design of the driver-receiver pair circuit resulting in robust and wide operating bias margins, current management on the floating islands, etc. This thesis investigates SB in a systematic manner, focusing on the design and measurement of the fundamental components of this technique with an emphasis on reliability and scalability. It presents works on circuit techniques achieving high speed serially biased RSFQ circuits with robust operating margins and the experimental evidence to support the ideas. It develops a framework for serial biasing that could be used by electronic design tools to automate design and synthesis of complex RSFQ circuits. It also investigates Passive Transmission Lines (PTLs) for use as passive interconnects between library cells in a complex design, reducing the DC bias current required by the active circuitry.

M. S.

This thesis presents an interactive graphics-based FORTRAN program which aids the process of implementing a digital system with wirewrap² circuit boards. Integration of the program into the stream of design process steps is considered and details are presented concerning the development of the interactive graphics subsystem of the program. The user has complete freedom in specifying the location of integrated circuit units on the board. The program provides drawings of both sides of the circuit board, a listing of wirewrap wiring instructions and an equation list of the digital system. Some improvements and refinements of the program are suggested. / M. S.

With electronic packaging becoming more complex, simple hand methods to model the thermal performance of the package are insufficient. As computer aided modeling methods came into use, a test system was developed to verify the predictions produced by such modeling methods. The test system is evaluated for operation and performance. Further, the premise of this type of test (the accurate calibration of packaged temperature-sensitive-parameter devices can be done) is investigated using a series of comparative tests. From this information, causes of possible/probable errors in calibration are identified and related to the different methodologies and devices used. Finally, conclusions are presented regarding the further improvement of the test system and methodologies used in this type of testing.

by Lo Wing-yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves vii-ix). / ABSTRACT --- p.i / LIST OF TABLES --- p.iv / LIST OF FIGURES --- p.v / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 1.1 --- Traditional Design Prototyping --- p.1 / Chapter 1.2 --- In-Circuit Rapid Prototyping System --- p.2 / Chapter 1.3 --- A Summary of Prototyping Systems Available --- p.5 / Chapter 1.4 --- Universal Prototyping Board (UPB) --- p.6 / Chapter 2. --- HARDWARE DESIGNS --- p.9 / Chapter 2.1 --- Bus Interconnection --- p.9 / Chapter 2.1.1 --- Fixed buses --- p.9 / Chapter 2.1.2 --- Programmable buses --- p.12 / Chapter 2.2 --- Architectural Features --- p.15 / Chapter 2.2.1 --- Field programmable gate array --- p.15 / Chapter 2.2.2 --- Microprocessor --- p.15 / Chapter 2.2.3 --- Memory --- p.16 / Chapter 2.2.4 --- Buffers --- p.18 / Chapter 3. --- SOFTWARE TOOLS --- p.20 / Chapter 3.1 --- Critical Path Analysis --- p.20 / Chapter 3.1.1 --- Algorithm of critical path analysis --- p.21 / Chapter 3.1.2 --- Computation time --- p.21 / Chapter 3.2 --- Circuit Partitioning --- p.23 / Chapter 3.2.1 --- Partitioning algorithm --- p.24 / Chapter 3.2.2 --- Effects of partitioning --- p.36 / Chapter 3.2.3 --- Partitioning parameters --- p.38 / Chapter 3.2.4 --- Pseudo-code of partitioner --- p.39 / Chapter 3.3 --- IO Assignments --- p.40 / Chapter 3.3.1 --- Connect 4 FPGAs --- p.40 / Chapter 3.3.2 --- Connect 3 FPGAs --- p.42 / Chapter 3.3.3 --- Connect 2 FPGAs --- p.44 / Chapter 3.3.4 --- System IO (Connect 1 FPGA) --- p.47 / Chapter 3.4 --- Other Tools --- p.48 / Chapter 4. --- STRUCTURE ANALYSIS --- p.49 / Chapter 5. --- RESULTS --- p.52 / Chapter 6. --- FUTURE DIRECTION --- p.73 / Chapter 6.1 --- Other Possible Configurations --- p.73 / Chapter 6.2 --- Programmable Interconnection --- p.73 / Chapter 6.3 --- Expandability of UPB --- p.74 / Chapter 7. --- CONCLUSION --- p.75 / BIBLIOGRAPHY --- p.vii / APPENDICES --- p.x

Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 79. / by Edwin P. Berlin, Jr. / B.S.

Thesis. 1975. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / Vita. / Bibliography: leaves 237-242. / Ph.D.

With the introduction of the floating-gate transistor into reconfigurable architectures, great advances have been made in the field. Recently, Hall et. al. have proposed the first truly large-scale field programmable analog array (FPAA). As an outgrowth of this work, a new class of FPAAs based on translinear elements has begun to be developed. The use of translinear elements, multiple input translinear elements (MITEs) specifically, allows for extreme versatility in the functions implemented by the system while keeping the computational elements of the FPAA regular. In addition, synthesis procedures have been developed for translinear elements. This facilitates the implementation of large-scale systems on the FPAA because the circuit design can be extracted using the synthesis procedures based on equations entered by the user. Two architectures are proposed for the new FPAA. The first architecture uses fine grain reconfigurability, every gate capacitor and the drain of each MITE can be connected arbitrarily, in order to create reconfigurable MITE networks. Circuits including a squaring circuit, a square root circuit, a translinear loop, a vector magnitude circuit, and a 1st-order log-domain filter were implemented using this architecture and results are presented. In addition, examples are shown to illustrate the compilation of the circuits onto the FPAA. The second proposed architecture uses a mix of fine and medium granularity in order to simplify the implementation of larger systems. Examples are given and again the compilation of the circuits onto the FPAA is shown.