MILITARY HANDBOOK ELECTRONIC RELIABILITY DESIGN …

1 NOT MEASUREMENTSENSITIVEMIL-HDBK-338B1 October 1998 SUPERSEDINGMIL-HDBK-338A12 October 1988 MILITARY HANDBOOKELECTRONIC RELIABILITY DESIGN HANDBOOKThis HANDBOOK is for guidance only. Do not cite this documentas a requirementAMSC N/AAREA RELIDISTRIBUTION STATEMENT A. Approved for public release; distribution is HANDBOOK is approved for use by all Departments and Agencies of theDepartment of Defense (DoD). It was developed by the DoD with the assistance ofthe MILITARY departments, federal agencies, and industry and replaces in its entiretyMIL-HDBK-338A. The HANDBOOK is written for RELIABILITY managers and engineersand provides guidance in developing and implementing a sound RELIABILITY HANDBOOK is for guidance HANDBOOK cannot be cited as arequirement. If it is, the contractor does not have to is a discipline that continues to increase in importance as systemsbecome more complex, support costs increase, and defense budgets has been a recognized performance factor for at least 50 years.

2 DuringWorld War II, the V-1 missile team, led by Dr. Wernher von Braun, developedwhat was probably the first RELIABILITY model. The model was based on a theoryadvanced by Eric Pieruschka that if the probability of survival of an element is 1/x,then the probability that a set of n identical elements will survive is (1/x)n . Theformula derived from this theory is sometimes called Lusser s law (Robert Lusser isconsidered a pioneer of RELIABILITY ) but is more frequently known as the formula forthe RELIABILITY of a series system: Rs = R1 x R2 x .. x the long gestation period for RELIABILITY , achieving the high levels needed inmilitary systems is too often an elusive complexity, competingperformance requirements, the rush to incorporate promising but immaturetechnologies, and the pressures of acquisition budget and schedule contribute to thiselusiveness.

3 In the commercial sector, high levels of RELIABILITY are also , American products once shunned in favor of foreign alternatives havemade or are making a comeback. This shift in consumer preferences is directlyattributable to significant improvements in the RELIABILITY and quality of theAmerican these improvements, and facing a shrinking defense budget, the Departmentof Defense began the process of changing its acquisition policies to buy morecommercial off-the-shelf products and to use commercial specifications andstandards. The objective is to capitalize on the best practices that Americanbusiness has developed or adopted, primarily in response to foreign combined with the knowledge and expertise of militarycontractors in building complex and effective MILITARY systems (soundlydemonstrated during the conflict with Iraq), it is hoped that these commercialpractices will allow the Department of Defense to acquire world-class systems ontime and within information in this HANDBOOK reflects the move within the MILITARY toincorporate best commercial practices and the lessons learned over many years ofacquiring weapon systems by the book.

4 MILITARY as well as commercial standardsand handbooks are cited for reference because they are familiar to both MILITARY andcommercial companies. Many of the MILITARY documents are being rescinded, socopies may be difficult to obtain. For those who have copies or can obtain them,the MILITARY documents provide a wealth of valuable comments (recommendations, additions, deletions) and any pertinentdata which may be useful in improving this document should be addressed to: AirForce Research Laboratory/IFTB, 525 Brooks Road, Rome, NY should be submitted using the self-addressed Standardization DocumentImprovement Proposal (DD Form 1426) appearing at the end of this document orby OF CONTENTSiiiTABLE OF ..0 REFERENCED Documents .. , Standards and Handbooks .. Referenced Documents .. OF TERMS AND ACRONYMS AND ABBREVIATIONS .. of Abbreviations and STATEMENTS.

5 And Background .. System Engineering Process .. Engineering and IPTs .. Four Steps of Systems Engineering .. Effectiveness .. Considerations in System Effectiveness .. Influencing System Effectiveness .. of New DESIGN .. Among Various System Properties .. of System Effectiveness ..4-115 .0 RELIABILITY /MAINTAINABILITY/AVAILABILITY THEORY .. Theory .. Concepts .. Distributions Used in RELIABILITY Models .. Distributions .. (or Gaussian) Distribution .. of RELIABILITY Calculations Using the Normal Tube Example .. Equipment Example .. Distribution .. Failure Example ..5-17 MIL-HDBK-338 BTABLE OF CONTENTSivTABLE OF Distribution .. Fire Control System Example .. Example .. Distribution .. System Example .. Distribution .. of Use of Weibull Distribution .. Distributions .. Distribution .. Quality Control Example .. RELIABILITY Example.

6 Distribution .. With Permissible Number of Failures .. Modeling .. Failure Rate Curve .. Modeling of Simple Structures .. Configuration .. Configuration .. Configuration .. Statistics in RELIABILITY Analysis .. Theorem .. Example (Discrete Distribution) .. Example (Continuous Distribution) .. Theory .. Concepts .. Distributions Used in Maintainability Models .. Distribution .. ELECTRONIC System MaintainabilityAnalysis Example .. Distribution .. Example .. Distribution .. Example .. Approximation .. Theory .. Concepts .. Modeling (Markov Process Approach) .. Unit Availability Analysis(Markov Process Approach) ..5-75 MIL-HDBK-338 BTABLE OF CONTENTSvTABLE OF Trade-Off Techniques .. vs For Section 5 ..5-886 .0 RELIABILITY SPECIFICATION, ALLOCATION, MODELING ANDPREDICTION .. Specification .. of Specifying the RELIABILITY of Environment and/or Use Conditions.

7 Measure or Mission Profile .. Definition of Failure .. of Method(s) for RELIABILITY Demonstration .. Apportionment/Allocation .. Apportionment Technique .. Apportionment Technique (Ref. [6]) .. Technique (Ref. [7]) .. of Effort Algorithm .. Modeling and Prediction .. Procedure .. Definition .. Use Profile .. Block Diagrams .. Models .. Description .. Data .. Analysis .. Distributions .. Rates .. Item RELIABILITY .. RELIABILITY Models and Predictions .. Modeling .. Block Diagrams .. Modeling Methods .. Probability Modeling Method .. Series Model .. Parallel Models .. Series-Parallel Models .. Truth Table Modeling Method ..6-33 MIL-HDBK-338 BTABLE OF CONTENTSviTABLE OF Diagram Modeling Method .. System Modeling Methods .. Markov Modeling (Ref. [9]) .. Monte Carlo Simulation Method .. Prediction .. Models for RELIABILITY Prediction.

8 Prediction Methods .. Item Prediction Method .. Count Prediction Method .. Stress Analysis Prediction Method .. Stress Analysis Techniques .. Sample Calculation .. Modification for Non-Exponential FailureDensities (General Case) .. Nonoperating Failure Rates .. RELIABILITY Physics Analysis (Ref. [17] and [18]) .. Aided RELIABILITY Prediction .. Procedure for Performing RELIABILITY Prediction and Allocation .. for Section 6 .. ENGINEERING DESIGN GUIDELINES .. Management .. a Preferred Parts List (PPL) .. and Device Selection .. Devices/Technology/Vendors .. Devices .. and MMIC Devices .. Encapsulated Microcircuits (PEMs) .. Hybrids .. Specifications .. Obsolescence and Diminishing ManufacturerSources (DMS) .. Reporting, Analysis, And Corrective ActionSystem (FRACAS) .. for RELIABILITY .. Part RELIABILITY Assessment / Life Analysis.

9 For Manufacturability ..7-19 MIL-HDBK-338 BTABLE OF CONTENTSviiTABLE OF Management Plan Evaluation Criteria .. Improvement Program .. Assurance .. Qualification .. Quality Assurance .. Processes .. Criteria .. Part Derating .. of Mechanical and Structural Components .. Circuit DESIGN .. and Overstress Protection .. Protection Networks .. Oxide Varistors (MOVs) .. Diodes .. Controlled Rectifier Protection .. Component Protection .. Devices Summary .. DESIGN For Parts, Assemblies and Equipment .. Wiring Board Layout .. Grounding .. Protection With MOVs .. Protection With Diodes .. Degradation and Circuit Tolerance Analysis .. Aided Circuit Analysis .. of Computer Aided Circuit Analysis/Simulation . of Computer-Aided Circuit Analysis/SimulationPrograms .. Personal Computer (PC) as a Circuit Analysis Tool .. DESIGN Limitations.

10 Voltage Gain Limitation .. Gain Limitation Considerations .. Factors .. Tolerant DESIGN .. Techniques .. on Testability .. Role in the Fault Tolerant DESIGN Process .. Tolerant DESIGN Analysis ..7-86 MIL-HDBK-338 BTABLE OF CONTENTS viiiTABLE OF as a DESIGN Technique .. of Redundancy .. Notation for Redundancy Computations .. Combinations .. in Time Dependent Situations .. Considerations in DESIGN .. Redundancy .. Standby Redundancy .. Parallel Elements .. Parallel Elements .. Redundancy .. Standby Redundancy .. Failure Probabilities .. Allocation of Redundancy .. Analysis Using Markov Modeling .. Theory .. of the Markov Model Equation .. Model Reduction Techniques .. of Coverage to Markov Modeling .. Conclusions .. DESIGN .. Strength .. for the Environment .. Protection.