1. Solder voids suspected: Wondering if there is a specification for acceptable percentage of solder void on the heat sink, Cu pad that resides under the chip? PCB vendor claims that a 30% solder void on the heat sink, Cu pad under the chip is within his specified tolerances for mfg. From our initial investigation, it appears that the void may exceed 50%. Could this be one culprit for overheating and shortened lifespan?
2. Data sheet recommended number (of 10 mil radius) vias through the heat sink Cu pad (to ground plane or other) is five. What if there was only one or two vias through the Cu pad (to ground plane or other). Could this be another culprit for overheating and shortened lifespan?
