SR TSY 000385 : ISSUE 1

PREFACE
LIST OF NOTATIONS
LIST OF ABBREVIATIONS
LIST OF FIGURES
LIST OF TABLES
SELECTED DEFINITIONS
INTRODUCTION
1 RELIABILITY CONCEPTS
1.1 Reliability Definitions
1.2 A Mathematical Look at Failure
                      Distributions, Reliability, and
                      Failure Rates
1.2.1 Cumulative Distribution Function
1.2.2 Reliability Function
1.2.3 Probability Density Function
1.2.4 Failure Rate (Hazard Rate)
1.2.5 Example 1-1
1.3 Device Failure Rate Model
1.4 The Exponential Distribution
1.5 Mean-Time-To-Failure and
                      Mean-Time-Between-Failures
1.6 Availability
1.7 Operation With or Without Replacement
1.8 Measures of Reliability
1.8.1 Example 1-2
1.9 Considerations in the Early Life
                      or Infant Mortality Period
1.9.1 Example 1-3
1.10 Considerations in the Steady-State Region
2 DEVICE RELIABILITY
2.1 Long Term Reliability
2.1.1 Accelerated-Stress Testing
2.1.2 Time-Temperature Relationship
                      (Arrhenius Equation)
2.1.3 Life Distribution
2.1.4 Freaks
2.1.5 Failure Mechanisms in Accelerated Testing
2.1.6 Influence of Design on Long-Term
                      Device Reliability
2.1.7 Qualification and Lot Acceptance Testing
                      of Electronic Devices
2.1.8 Effects of Temperature and Electrical
                      Stress on Long-Term Failure Rates
2.2 Early Life Reliability (Infant Mortality)
2.2.1 Device Infant Mortality Defects
2.2.2 Infant Mortality Modeling
2.2.3 Effects of Temperature on Infant
                      Mortality Failure Rates
2.2.4 Infant Mortality Screening
2.2.5 Burn-in
2.2.6 Example 2-2
3 SPECIFIC DEVICE INFORMATION
3.1 Capacitors
3.1.1 Ceramic
3.1.2 Electrolytic - Aluminium
3.1.3 Electrolytic - Solid Tantalum
3.1.4 Glass
3.1.5 Mica
3.1.6 Paper
3.1.7 Plastic
3.1.8 Silicon Chip
3.1.9 Variable
3.2 Connections
3.2.1 Description of Connections and
                      Reliability Considerations
3.3 Connectors
3.3.1 Description of Connectors
3.3.2 Nature of Connector Failures
3.3.3 Factors Affecting Connector Reliability
3.4 Inductors and Transformers
3.4.1 Definitions
3.4.2 Common Failure Modes
3.4.3 Conditions Affecting Long-Term Failure
3.4.4 Testing for Fail-Safe Operation
3.5 Integrated Circuits
3.5.1 Voltage-Sequence Sensitivity
3.5.2 Complementary Metal-Oxide
                      Semiconductor (CMOS)
3.5.3 Digital Bipolar
3.5.4 Gated Diode Crosspoint Switch
3.5.5 Linear Bipolar
3.5.6 Memory - Soft Errors
3.5.6.1 Nature of Soft Failures
3.5.6.2 Alpha Emission in VLSI Packages
3.5.6.3 Estimation of Error Rate for a Device
3.5.6.4 Device Characterization
3.5.6.5 Actions Available to System Engineers
3.5.6.6 Methods of Error Correction in Systems
3.6 Opto-Electronics
3.6.1 Laser Transmitters for Optical
                      Communication
3.6.2 Light-Emitting Diodes - Displays and
                      Illuminators
3.6.3 Light-Emitting Diodes - Transmitters for
                      Optical Communication
3.7 Printed Circuits
3.7.1 Failures During Useful Life
3.7.2 Wearout Phenomena
3.7.3 Factors Affecting Printed Circuit
                      Reliability
3.8 Relays
3.8.1 Sealed Contact
3.8.2 Sealed Relays
3.8.3 Exposed Contact Relays
3.8.4 Preferred Materials Used in Relays
3.8.5 Nature of Relay Failures
3.8.6 Factors Affecting Relay Reliability
3.8.7 Information Sources
3.9 Resistors
3.9.1 Carbon Composition
3.9.2 Metal Film
3.9.3 Wirewound
4 RELIABILITY IN EQUIPMENT DESIGN
4.1 Reliability Engineering Concepts
4.2 Modeling System Reliability
4.2.1 Series Systems
4.2.2 Parallel Systems
4.2.3 r-out-of-n Systems
4.2.4 Example 4-1
4.2.5 Analysis of More Involved Reliability
                      Block Diagrams
4.2.6 Example 4-2
4.2.7 Summary
4.3 Equipment Reliability Estimation
4.3.1 Estimating the Effects of Temperature
                      and Electrical Stress
4.3.2 Effects of Environment and Circuit
                      Application
4.4 Long-Term Reliability Estimates
4.4.1 Series Systems
4.4.2 Example 4-3
4.4.3 Nonseries Systems
4.4.4 Example 4-4
4.5 Infant Mortality Estimates
4.5.1 Series Systems
4.5.2 Nonseries Systems
4.5.3 Example 4-5
4.5.4 Renewal
4.5.5 Example 4-6
4.5.6 Reducing Infant Mortality Failure Rates
4.5.7 Example 4-7
5 (Section 5 is left blank for future use)
6 BELLCORE RELIABILITY PREDICTION PROCEDURE
                      FOR ELECTRONIC EQUIPMENT
7 MAINTAINABILITY
7.1 General Discussion
7.1.1 Replacement Rate (RIT) During the
                      Constant Failure Rate Region
7.1.2 Replacement Rate (RIT) During the Infant
                      Mortality Region
7.2 Maintenance Spares
7.2.1 Estimation of Number of Spares for the
                      Constant Failure Rate Region
7.2.2 Example 7-1
7.2.3 Estimation of Number of Spares for the
                      Infant Mortality Region
7.2.4 Example 7-2
7.2.5 Guidelines for Ensuring Optimal
                      Utilization of the Sparing Concepts
7.3 Repair Charges-Recurring
7.3.1 Example 7-3
7.4 FIT Predictions
7.5 RIT Acceptance Procedures
7.5.1 RIT Acceptance Bounds (Limits)
7.5.2 Example 7-4
7.5.3 Summary of Field Analysis Procedure
8 SUPPLEMENTARY INFORMATION
8.1 References
8.2 Bibliography
LIST OF TABLES
2-1 Log-normal Mathematical Functions
2-2 Examples of Reliability Assurance
                      Requirements
4-1 Boolean Truth Table
7-1 Usco Adjustment Factor
7-2 Service Continuity Objectives

This manual compiles, in a single volume, Bellcore's view of reliability concepts,, methods & data for suppliers (& designers) of telecommunications equipment for use in a BOC. Four main topics are covered: 1. Methods of estimating availability & reliability. 2. Methods of improving equipment reliability when necessary. 3. Guidelines for monitoring equipment reliability through testing. 4. Techniques for estimating number of spares needed to achieve certain reliability levels.