Optimizing test strategies during PCB design for boards with limited ICT access

Engineers have used past experience or subjective preference as a means for assigning test strategies to new products without analyzing the benefits and weaknesses of various different test approaches in a quantitative manner. DFT (design for test) software tools that enable testability analysis during board design allow test engineers to work concurrently with designers. Case study results demonstrate that coverage predicted by DFT software is realistic when compared to actual fault coverage achieved in production. Using DFT software during PCB design to model the fault coverage of different test strategies and make ICT (in-circuit test) access tradeoffs can significantly reduce cost and improve quality. Defect capture rates more than doubled when using alternate test strategies and production line beat rates varied significantly depending on the test strategy chosen. When DFT software enables these decisions early in the product life cycle, both OEMs and EMS providers can win by driving cost reductions through the entire product life cycle from NPI (new product introduction) through manufacturing and warranty.