When inserting units with polarity needs, listen making sure that their polarity is notreversed. Roll built-in block components immediately after SMT. No matterwhether They can be vertical or horizontal areas, there have to be no apparent tilt. Telecom products, like satellites and base stations, frequently use 6-layer PCBs to handle https://10-layer-3-level-hdi-gold72605.madmouseblog.com/11690139/the-smart-trick-of-goldfinger-pcb-for-electronics-industry-that-no-one-is-discussing