There are several reasons why today’s power supplies can experience reliability issues, including solder joint fatigue as a top contributor. Space constraints and large components in a power supply can prove problematic for solder joints, along with thermal expansion issues that can occur during thermal cycling. To help effectively predict and mitigate potential solder joint fatigue in a device's power supply, an understanding of common problems that can arise, along with a proactive design and analysis strategy, can help conserve engineering resources and speed time to market.
Industry interest in producing thinner and smaller integrated circuit (IC) packages to match the performance of chip scale packages has resulted in the wide application of quad flat no-lead (QFN) components. However, the small-form factor of QFN packages can place solder joints at risk of coefficient of thermal expansion (CTE) mismatch, which can potentially lead to PCB warping and failure. To help mitigate this risk and accurately assess the fatigue life of solder interconnects in QFN packages, a predictive model incorporating the material and geometric parameters that influence solder joint fatigue should be used.