Worst Case Analysis
How Worst Case Circuit Analysis Saves $$$
Worst Case Circuit Analysis (WCCA or WCA) is a cost-effective means of screening a design to ensure with a high degree of confidence that potential defects and deficiencies are identified and eliminated PRIOR TO and DURING test, production, and delivery.
WCCA is not an after-the-fact exercise but a cost-effective integral part of the design process.
WCCA is not a candidate for elimination when there are cost overruns.
When a WCCA is performed properly, the results often save companies millions of dollars in lost revenue, dramatically lessen the possibility of human disaster, and avert potential disasters, both monetary and political.
Conducting a WCCA during the design phase should be a top consideration. The computer models should be constructed in parallel with the breadboards and/or EM’s. The models should be reviewed and updated for EVERY circuit or requirement change.
Should you do a WCCA? Here are some questions to ask yourself:
• How much risk can the program accept?
• What is the cost of failure?
• What is the heritage of the circuitry?
• What is the cost of doing or not doing a worst case analysis?
The typical cost of performing a rigorous WCCA is generally less than 1% of the program cost. The cost of not doing the WCCA can be 100% of the program cost. We have seen many program failures which required at the least, major redesigns AFTER completion of qualification testing. This costs enormous amounts of time and money.
Benefits From WCCA
Validate acceptable operation throughout the entire product life cycle under the most unfavorable combination of anticipated conditions [Worst Case Extreme Value Analysis (EVA)]
Define Critical Components and Spec. Control Drawing (SCD) Limits
Provide Acceptance Test Procedure (ATP) Limits
Define Need for and Range of Select-At-Test (SAT) components
Improve Reliability through Parts Stress and Derating Analysis
Identify design concerns which during test, alignment, and use, could result in circuit damage or premature degradation.
WCCA helps ensure increased product reliability. We accomplish this through rigorous
mathematical and simulation-based models, along with hardware correlation. Correlated
models are then used to determine part stress margins, and EOL/BOL product operating
specifications. A single over-stressed component can cost your company millions
of dollars. A thorough Worst Case Analysis can prevent this from happening.
Background & Definition
A Worst Case Circuit Analysis is a quantitative assessment of the equipment performance, accounting for manufacturing, environmental and aging effects. In addition to a circuit analysis, a WCCA often includes a stress and derating analysis, a Failure Modes and Effects Criticality analysis (FMECA) and a Reliability Prediction (MTBF).
The specific objective is to verify that the design is robust enough to provide operation which meets the system performance specification over the design life under worst case conditions and tolerances (initial, aging, radiation, temperature, etc.).
Recent AEi Systems Clients
• Allied Signal
• BAE Systems
• Boeing (Space, B1)
• Brookhaven National Labs
• EB Aerospace
• Florida Power and Light
• Frequency Electronics
• General Dynamics
• Hamilton Standard
• Hughes Space and Communications
• International Rectifier
• ITT Industries
• Linear Technology
• Lockheed Martin (CA, CO, PA)
• MIT Lincoln Labs
• M.S. Kennedy
• Northrop Grumman
• Pedestal Networks
• Signal Technology
• Sierra Microwave Technology
• Smith & Nephew
• Space Systems Loral
• Spinnaker Microwave
• Taber Industries
• TRW Space and Technology
• Texas Instruments
• Watkins Johnson
● Space Station
● GPS IIF
● GPS III