Method for Improving Design Testability through Modeling

Testability modeling has been performed for many years. Unfortunately, the modeling of a design for testability is often performed after the design is complete. This limits the functional use of the testability model to determining what level of test coverage is available in the design. This information may be useful to help assess whether a product meets a requirement to achieve a desired level of test coverage, but has little pro-active effect on making the design more testable. This paper will layout the reasons for adding testability modeling to design effort and the process by which modeling can be effectively utilized to improve an electrical designs' testability. It will cover some of the assumptions that must be made initially about testability at a programs onset, the phases in a programs lifecycle that testability modeling should be performed, the level of detail that a testability model should contain, the review and other processes that should be used to validate the model and determine if design modification/improvements should be performed, as well as the way testability should be incorporated into a program's overall test strategy. The information related in this document is based upon the personal experience of the author as the company he works for attempts to better utilize new and existing design tools and processes to improve the manufacturability of its designs and reduce the overall cost of its products in an ever more challenging defense acquisition environment.