Moisture-sensitivity testing (MSL) of flange-mounted packages is performed using the Joint Industry Standard IPC/J-STD-020C guidelines for surface mount technology (SMT) packages. Although the same testing methodology is required for all standard SMT packages, such as SOP, QFP, and TSOP, flange-mounted and SMT packages with exposed die paddle require additional testing to properly assess the MSL performance of the package and its reliability for lead-free processing. This application report explains methodologies that can be used to assess and improve the robustness of flange-mounted and SMT packages with exposed die paddle and down bonds.