Developing built in test to meet the demands of the product test lifecycle

Companies are incorporating Built-In-Test (BIT) capabilities into their products to 1) reduce the need for external Special Test Equipment (STE), 2) incorporate test capability for all levels of manufacturing test from Circuit Card Assembly (CCA) to the finished product, 3) decrease the test/diagnostics cycle time, and 4) product logistics test needs in the field. Customer BIT requirements are typically phrased as “BIT shall be used as the final verification of the product assembly” or “The product shall have a 95% BIT coverage”. These vague requirements can leave the BIT Developer overwhelmed with the interpretation of the “how” to create a BIT or “what is BIT” to successfully meet the customer's needs. This paper provides a BIT development methodology and process that defines the “how” and “what” to meet both the needs of the customer and to provide beneficial capabilities to increase product test effectiveness while decreasing cost of test. The “how” defines the development process of Built-in-Test artifacts as it progresses through the various development phases: requirements derivation, design evolution, test integration and validation, and finally deployment for production and field maintenance. The “what” discusses the selection and definition of Built-in-Test artifacts for the product, selected through design methodologies such as testability design and modeling analyses.