Showing papers on "Physical design published in 1978"

Computer-aided layout design

Abstract: Within the general problem area of location problems, the layout planning problem or facilities location problem has for years attracted the attention of building planners (architects, industrial engineers) and operations researchers.

Wafer-scale integration-a fault-tolerant procedure

Abstract: Considers a new approach to full-slice technology in relation to existing procedures for achieving this goal. Under external control a chain of good chips is created to form a long serial memory from an array of identical chips on a full slice. Bad chips are automatically bypassed without requiring any pre- or post-programming of the metallization and without any prior knowledge of the distribution of faulty chips on the wafer. Computer simulations of chain formation are described which demonstrate the feasibility of creating such serial memories at practicable dice-yield levels. The proposed logic design is summarized and its verification by TTL simulation is noted. The inherent fault and failure tolerance of the design are discussed and the potential problem areas of short-circuit chips, double-level metallization, spiral branching, thermal dissipation, and noise/pattern sensitivity are described together with suggested solutions.

Methods for Hierarchical Automatic Layout of Custom LSI Circuit Masks

Abstract: A new automatic IC mask layout code is described which avoids most of the problems inherent in the present generation of layout codes such as lack of flexibility, inefficient use of area, and restricted design complexity. The structured hierarchical layout approach, construction graphs, and placement and routing algorithms are outlined.

A Technology-Relative Computer-Aided Design System: Abstract Representations, Transformations, and Design Tradeoffs

Abstract: This paper discusses the approach to global optimization taken in the C-MU register-transfer level computer-aided design system, currently under development at Carnegie-Mellon University, and gives examples of its application.

Register-Transfer Level Digital Design Automation: The Allocation Process

Abstract: This paper presents a portion of the register-transfer level computer aided design (RT-CAD) research at Carnegie-Mellon University. This part of the research involves the design and construction of an allocator, consisting of a set of algorithms and data structures which synthesize hardware at the logical level from a behavioral description. Preliminary results indicate the allocators performance compares favorably with a human designer.

ICARUS: An Interactive Integrated Circuit Layout Program

Abstract: ICARUS (Integrated Circuit ARtwork Utility System) is a software system which allows the user to create and modify an integrated circuit layout directly on a refresh CRT screen. The system can generate check plots on the matrix type printers available from Versatec or on a raster-scan laser printer such as the 9700 Xerox has recently announced. The ICARUS files can be used to create standard pattern generation tapes from which integrated circuit masks can be made. All the software to accomplish these various steps runs on a small experimental minicomputer known as the Alto.

Dynamic depletion mode: an E/D MOSFET circuit method for improved performance

Abstract: A new method of designing enhancement/depletion (E/D) MOSFET circuits, involving the dynamic or pulsed use of depletion-mode devices, is described. The method can result in improvements in performance and/or power in the design of memory, logic, and driver circuits. The method is compared with the standard approach to the design of E/D circuits. Several circuits designed by the method have been simulated by use of a numerical circuit analysis program and have been placed on an experimental test chip. Theoretical and experimental results are presented.

Supply-current analysis (scan) as a screen for bipolar integrated circuits

Abstract: A novel technique utilising the analysis of supply-current variations is proposed as a screen for digital integrated circuits. The application of the method to a simple m.s.i. circuit is used to demonstrate its capability of indicating the presence of flaws at internal circuit nodes.

An Interactive Graphics System for the Design of Integrated Circuits

Abstract: IGS (Interactive Graphics System) is a computer design aid specifically developed for the layout of integrated circuits User specification of process information makes the system process-independent while retaining the features which make it a useful layout tool The ability to place interconnect on a coarse grid greatly diminishes the chances of misalignment Automatic, incremental checking of cell-to-cell, cell-to-component, and component-to-component spacing reduces the number of design rule violations Rudimentary forms of topology verification are provided in the ability to trace electrical connectivity

An Integrated System for Interactive Editing of Schematics, Logic Simulation and PCB Layout Design

Abstract: This paper describes the basic concepts and features of an integrated PCB design system currently under development. The system includes facilities for interactive editing of schematics, logic simulation, placement and routing. A set of postprocessors will enable the designer to generate the necessary documents and drawings. The central part of the system consists of a Design File (DF) in which the different design steps are linked together. Once the schematic drawing has been produced, utilizing the versatile interactive graphic facilities in CASS (Computer Aided Schematic System), the schematic data will be automatically translated to a topological circuit description, which in turn will be exploited by the logic simulator and the layout system. The use of simulation during the design process is considerably simplified by operating the simulator from an interactive graphic terminal.

Implementation of an Interactive Printed Circuit Design System

Abstract: This paper describes the implementation and performance of SPRINT, an interactive system for printed circuit board design developed at the Stanford Linear Accelerator Center (SLAC). Topics discussed include the placement subsystem, the routing subsystem consisting of an interactive manual router, an automatic batch router, and a via elimination program, as well as the structure of the design file around which the entire system is centered.

The SCALD Physical Design Subsystem

Abstract: The SCALD physical design subsystem is described SCALD supports the automatic construction of ECL-10K logic on wire wrap cards from the output of a hierarchical design system Results of its use in the design of an operational 15-MIPS 5500-chip processor are presented and discussed

Modular bipolar analysis: Part II—Application

Abstract: This paper describes the application of a generalized modular model that is used to analyze realistic bipolar junction devices and integrated circuits from physical geometries and impurity profiles. A n-p-n transistor is partitioned into simple one-dimensional modules which enables a closed recursive equation to be used in solving for their electrical parameters. (See companion paper [13].) The individual module solutions are then superimposed upon the physical structure of the transistor to obtain its intrinsic electrical parameters. The advantages of using the recursive equation in performing ac, dc, and transient circuit analyses are simplicity and flexibility without a significant loss in accuracy. The application used to demonstrate this is the optimization and characterization of an Integrated Injection Logic (I2L) gate delay measured by an 11-gate ring oscillator. The agreement between the predicted and measured propagation delay is within 10 percent.

Interactive Specification of Structured Designs

Abstract: In structured design a design is expressed in high-level components, which are defined in terms of lower-level components. Structured design combines design information of all levels in one consistent data structure. It promotes a top down design and a bottom-up implementation. High-level components are partitioned into more and more detailed components, whereas low-level components are used to build more and more complex building blocks.The components of a design communicate only through well defined interfaces and are otherwise isolated from each other. This increases the modularity of a design, and is a first step towards technology-independent design. A design can be recompiled as new design primitives become available. Capturing the structure of the design also facilitates machine processing, such as logic simulation and verification, automatic placement and layout.Structured design greatly improves the ability to understand and maintain a design. It increases the correctness of a design, it makes the designer more productive and shortens the design cycle. Finally, the design itself serves as accurate documentation.

UNIX time-sharing system: Circuit design aids

Abstract: The circuit design engineer who wants to obtain rapid prototype construction of one-of-a-kind designs can get help by using programs that run under the UNIX∗ operating system. The programs include means for drawing circuit schematics on a graphics terminal and semi-automatic production of wire lists from those drawings. Included in the package are programs that check for simple errors and an interactive graphics program for performing the physical design of a circuit board. The design aids are oriented toward the production of circuits composed mainly of dual in-line packages mounted on wire-wrap boards. While the graphic editor, called draw, can be used for many purposes, the physical design layout program, called place, is valid only for boards equipped with sockets for dual in-line packages. The programs know how to prepare numerical control information for automatic and semiautomatic wire-wrap machines. The programs use a PDP-11 computer with a Tektronix 4014 graphics terminal attached. Hard copy graphic output is obtainable on some systems from a device attached directly to the terminal; otherwise, the data are transmitted over communications lines to a computing service machine.

Loop plant electronics: Physical design considerations

Abstract: The introduction of electronics into the loop plant has created the need for mounting electronic systems in the outdoors as well as in the central office. This article details the physical design considerations and requirements for the plug-in circuit boards, cabinets, closures, and hardware, and their interconnection to the telephone plant. Of particular interest is the product-line diversity from the small voice frequency range-extension devices and analog carrier systems to the large digital carrier and voice frequency loop switching systems. Each requires unique electrical and mechanical partitioning to optimize performance. Other critically important considerations are the cost-performance tradeoffs in a cost-sensitive market; the analysis, testing and evaluation of the system in environmental extremes of temperature, humidity, and atmospheric pollutants; the need to be compatible with existing loop plant hardware; and, lastly, the human factors considerations necessary to provide an effective interface with the telephone craftsperson. Specific designs are discussed which illustrate the practical problems encountered in meeting these requirements. In addition, the future thrust of loop electronics is discussed.

Grid Layout and Versatile Cells for Custom LSI Designers

Abstract: The association of versatile cells and coarse grid brings an efficient solution to the problem of designing performant custom LSI circuits. The CAD programs available allow direct wiring control, logical simulation as well as test pattern generation to ensure error free design of the final layout. This method has been successfully applied to TTL-LS technology.

Influence of circuit layout and packaging on fast computer performance

Abstract: As the speed of integrated circuits improves, the contribution of the interconnections between the circuits becomes more important and may be the dominant factor in the system performance. To establish a criterion for comparison of future developments, some current construction techniques are examined in detail, and the connection distances plotted as a function of the size of the subunits connected. It is shown that the connection distances vary approximately as the square root of the number of chips to be interconnected, although this relationship can be improved by careful layout and physical design of the system. To make a further significant improvement in packing density, it is necessary to remove the packages from the integrated circuits and mount several together on a common assembly. A memory system using such techniques is compared with previous systems, and it is shown that with a basic circuit-speed improvement of a factor of 3.8, the overall system speed may only be improved by a factor of 3 without packaging improvements, but that an improvement of 4.4 times can be obtained with better packaging.

Very large scale integrated circuit with integral test circuit - has counter, combination circuit and selection switch with shift register

Abstract: The very large scale integrated circuit VLSI) is provided with an integral test circuit. The test circuit includes a counter (3), a combination circuit (4) and a number of selection switches (51-54, 5p). The circuit is used to multiplex a small number of test pads to provide testing facilities for the associated integrated circuit. Pref. the test circuit contains a shift register, by whose parallel outputs the selection switches are, controlled, which are connected to the test points. Pref. a delay circuit is connected to the reset input of the counter.

Pseudostatistical analysis of LSI circuits

Abstract: A method for simulating statistical circuit performance that uses process parameters as input variables, will be covered.

Towards an Integrated, Minicomputer based LSI Design System

Abstract: The traditional design procedure of an integrated circuit involves the intensive use of nonlinear circuit analysis programs at transistor level and an interactive or automatic graphic layout system. These software tools become more and more insufficient in handling the ever growing LSI circuits. A fully integrated systems design demands for a wide range of computer aids : circuit analysis programs, logic simulators, timing simulators, automatic layout systems, graphic design assistants, test pattern generators, ... Although each of these tools can be used independently, their efficiency is highly increased by linking them together in an integrated LSI design system. Such a system consists of a series of procedures interactively or automatically - which assists and controls the development of an integrated circuit from the global system concepts to the mask generation. To reduce both design time and cost, an in-house-minicomputer should form the basic hardware configuration. However, coupling with a main frame increases the systems capability : the minicomputer acts as an intelligent terminal which handles input and output, while compute-bound tasks are send to the large computer. The designer-design system communication goes through a structural input description language, leading to a common data base for the entire design system.

A multifunction integrated circuit for automotive sensors

Abstract: The implementation and use of a unique and very versatile CMOS integrated circuit which converts changes in physical parameters such as capacitance or resistance into a pulse width modulated digital signal is described. The circuit has an additional output which can be used to indicate when a predetermined set-point has been reached. The circuit, in combination with resistive or capacitive sensors, can be used to provide digital inputs to microprocessors and other digital control and diagnostic systems. Several applications are described and the integrated circuit is discussed. The multifunction analog/digital integrated circuit interface chip along with appropriate sensors offers unique sensor systems which could be reliable, accurate and inexpensive.

The reliability of integrated circuits and systems from a manufacturing point of view

Abstract: The reliability of a system using integrated circuits is not an independent variable. Factors such as the system cost, capability, and complexity must also be considered as affecting reliability. By implication this also applies to each individual integrated circuit, to an extent determined by its inherent reliability and its influence in the system, which in turn depends on the system design, since functions may be implemented by either hardware (fixed functions) or software (programmable and usually more flexible).Some of the ways in which system requirements can affect the design, manufacture (including quality control), testing and quality assurance programmes (e.g. British Standard BS 9450) of large scale integrated circuits such as microprocessors, and the development of integrated circuit systems, having regard to reliability control, are discussed.