When inserting products with polarity requirements, pay attention making sure that their polarity is notreversed. Roll built-in block components after SMT. No matterwhether They may be vertical or horizontal elements, there have to be no evident tilt. Solder mask can be a significant polymer layer placed on the copper traces https://10-layer-5g-communication94726.csublogs.com/37854105/about-4-layer-high-power-goldfinger-power-supply-pcb