NASA Office of Logic Design

NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.


The NASA ASIC Guide: Assuring ASICs for SPACE

A Message from the NASA Office of Safety and Mission Assurance

This guide summarizes the Application Specific Integrated Circuit (ASIC) experience acquired by both NASA and industry. It reflects engineering principles that support current and future space programs.

Reliability must be an integral part of the systems engineering process. Weighed equally with other technical and program demands, applying sound reliability principles provides the key to an effective and affordable space program. Experience with America's space program shows that reliability efforts must focus on design characteristics that affect frequency of failure. Reliable ASICs can only come from complete, well-managed ASIC programs.

The guide seeks to make ASIC managers and designers astute consumers of ASIC technology, not to exhaustively teach proper ASIC design. It presents sound ASIC management and engineering practices, related to an overall methodology that comes from the current high-reliability ASIC industry.

I urge ASIC program managers to understand their specific ASIC design and system requirements, become involved in proper vendor selection, find out what contributes to excellent design implementation, and discover how to get the most from part acceptance without paying too much.

I urge ASIC engineers to put the same priority on testability and reliability requirements as you do on function and performance requirements. It's much better to design these qualities in from the beginning rather than force them into your ASIC at the end. This means that you must work hard up front to determine and clarify requirements, pick a good vendor, and then get the most out of that vendor's expertise.

NASA commissioned this guide because nothing like it exists today. To ensure that it remains a valuable source of information, parts of the guide will be updated as they become obsolete.

I believe this guide has a lot to offer the conscientious manager of a NASA ASIC program and I encourage you to refer to it often.


Frederick D. Gregory
Associate Administrator for
Safety and Mission Assurance


Acknowledgments

As managing editor, I would like to acknowledge the contributions of a number of individuals and organizations whose help has made it possible to carve a path through this difficult subject.

Primary authors:

Other contributors: ASIC Guide Overview Board:

I would particularly like to thank Jim Emerick of insyte, Rich Baldwin of Navy Crane, and Jerry Reinsma of UTMC for attending all of the ASIC Guide Overview Board meetings. Besides incisive editorial comments, they brought a very healthy dose of real world perspective to the guide. This would be a much-diminished work without their contributions.

For their detailed review of the guide's ASIC design material, I would like to thank Dave Polak, Ian Macdonald, Joe Hoffman, and John Boquet of IBM; Harry Gardner, Jerry Reinsma, and Rich Nuth of UTMC; Peter Brooks, Don Koch, John Reeser, Nick van Vonno, and Scott Brandt of Harris; Rod Clark, Dave Erstad, and Rob Rabe of Honeywell.

Thanks to Dan Barney of NASA Headquarters, Code QR, for sponsoring this work. I would also like to thank the following JPL managers for their support and suggestions: Larry Hess, Larry Wright, Earl Cherniack, and Jim Roberts.

More recently I'd like to thank several individuals for bringing the ASIC Guide to the Internet.

Mosaic Programmers/Translators/Gurus:

Finally, I owe a debt of gratitude to Anne Macdonald, whose abilities as a writer, copy editor, book designer, publication coordinator, etc., are reflected in the non-MIL-SPEC look of the guide, its clarity, and its readability.


James W. Wall
Managing Editor


About This Guide

When NASA awarded JPL the contract to build the Cassini spacecraft, the congratulations had not diminished before project management realized the design would call for ASICs. Though commonly used for commercial applications for a number of years, ASICs were new to the space industry. How could an industry that demands reliability take advantage of this new technology and minimize risk when no historical data existed for managing an ASIC program-particularly when "unique" describes the very nature of each ASIC? In short, ASICs represented a new frontier in space electronics. Cassini project leaders concluded that the key to ASIC reliability lay heavily in sound management of the ASIC program. From that conclusion the Cassini team developed an ASIC task list.

As the task list evolved, Cassini management asked: "Why not take this idea further and develop a complete guide to managing an ASIC program?" NASA endorsed the need and commissioned JPL to assemble the data and write this guide.

The NASA ASIC Guide draws from a broad range of ASIC experience. The JPL team called upon ASIC experts from the commercial world, academia, and numerous government agencies committed to high reliability microelectronics. A number of these experts agreed to sit on the NASA ASIC Review Board. The authors of the guide visited those in the field, such as NASA contractors and ASIC vendor customer support engineers, drawing from their experience. Combining the knowledge gained from the experts with the practical experience gained on the Cassini project, JPL developed the guide. Throughout the process, members of the NASA review board offered informed opinions as they critiqued the entire document.

JPL developed this guide to help NASA and NASA contractor communities obtain high-quality ASICs. The guide focuses on high reliability space applications, which frequently require radiation hardening to the natural space radiation environment. The authors provide a broad look at all the tasks involved in ASIC management and engineering, assuming sound managerial and engineering judgment prevails when actually implementing the details of your ASIC program.

Section One, "ASIC Management," addresses ASIC program managers by presenting ASIC management practices.

Section Two, "ASIC Vendor Evaluation," targets ASIC program managers and, to some extent, ASIC designers, quality assurance, and procurement personnel involved in the vendor selection process.

Section Three, "ASIC Design," explores core practices in design with an emphasis on simulation-based methodologies, as well as design for space applications, which includes design for the natural space radiation environment. The authors assume that the readers of Section Three have an electronic engineering background; a background in VLSI microelectronics would be helpful.

Section Four, "ASIC Part Acceptance," tries to extract from the complex world of government-controlled microelectronics part acceptance, those practices that make sense for ASIC part acceptance. Section Four targets the same audience as Section Two: ASIC program managers, ASIC designers, quality assurance and procurement personnel.

The Appendices deal at length with a set of issues related to ASICs. Each appendix expands on information introduced in the four primary sections.

The guide addresses digital ASICs, believing analog ASICs complex enough to deserve their own separate guide. Though the authors concentrate on well-established technologies and practices in the high-reliability ASIC industry, they chose to discuss field programmable gate arrays (FPGAs) because this emerging technology may soon become a standard approach.

All ASIC managers and designers face the task of translating a set of requirements into a deliverable ASIC device. This guide, which conforms to Total Quality Management commonly adopted throughout the space industry, provides a framework for accomplishing this translation, setting forth a methodology based on the following:

This guide has already proven useful for a number of ASIC programs. We trust it will prove useful to you.


We invite your comments

If you have any comments on this ASIC guide, please write or fax them to:

ASIC Guide Development Group
Mail Stop 125-105
JPL
4800 Oak Grove Drive
Pasadena, CA 91109-8099

FAX: (818) 393-5245

If you find any errors in this document, please notify Craig Persiko by e-mail at Craig_Persiko@hmc.edu


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