Accelerating Thermal Cycling Life TestingĮverything on a circuit board is not purely electrical. Read our Top 5 Reasons for Solder Joint Failure blog to learn more. Placement of the QFN in the resulting high-strain area could lead to solder joint failure of the QFN. During a thermal cycling event, you can see the high-strain areas (indicated by red and yellow) that develop.
In Figure 2, a QFN has been placed between two large inductors on a printed circuit board (PCB) with four corner standoffs. Near V-scored board edges, where breaking of the V-score may damage the part.Areas between or near larger stiff components (like inductors).With strain-sensitive components, it is important not to place them in high-strain areas on the board, such as: These components do not have compliant leads, and therefore only the solder is available to absorb the strain. There are several reasons why components can be sensitive to thermal cycling, including where a component is placed on a circuit board and the type of component, such as quad-flat no-lead (QFN) packages, ball grid arrays (BGAs), and ceramic capacitors. What Makes Components Sensitive to Thermal Cycling?
