Design and Surface Finish of Coil Boards
1 min
Circular coils are a wiring method sometimes used in PCB layout. They serve primarily as inductors, transformers, antennas, and more. Considering the production of PCBs containing coiled traces, please take note of the following points:
1. Compared to conventional circuits, it might not be possible to detect short circuits between windings of circular coils if the coil is a closed circuit. Therefore, the requirement for trace width and spacing is 0.254 mm (with a limit of 0.15 mm, but only when the coil is covered with soldermask).
2. For exposed copper in the coil, only ENIG process is recommended (which offers relative flatness and a tighter thickness tolerance).
3. It is not advisable to use the hot air solder leveling (HASL) process for coils with exposed copper (HASL has large thickness tolerance and is prone to solder bridging between coil windings).
4. Coils covered with soldermask can be processed with either hot air solder leveling (HASL) or ENIG.
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