Design for Board and System Level Structural Test and Diagnosis

The success of system test is measured by test quality and cost. System test quality and cost rely on several factors, such as component and board test quality, system test completeness, the support of system diagnostics, and a process that controls overall quality, resource and cost balances. Traditional structural test techniques used at the component level can achieve both high test quality and low test costs. This paper describes an approach to extend the functionalities of structural test techniques to the board and system level to improve the test accessibility, test time, and diagnostic capability. This approach has become practice in a large telecommunication company and the benefits received from this practice are tremendous. Examples will be given at the end of the paper.