5 Design
5.7 PCB documentation

Proper documentation is necessary to reduce the chance of misunderstandings and errors during the PCB manufacturing process. PCB producers need to know the exact requirements expected of their product, and assembly teams must understand how circuit boards fit into the final build.

The PCB documentation should include at least the hardware dimensional drawings, schematic, BOM, layout file, component placement file, assembly drawings and instructions, and the Gerber files.

The Gerber files are PCB jargon for the output files of the layout that are used by PCB manufacturers to create the PCB. A complete set of Gerber files includes output files generated from the board layout file [14]:

- Silkscreen top and bottom
- Solder mask top and bottom
- All metal layers
- Paste mask top and bottom
- Component map (X-Y coordinates)
- Assembly drawing top and bottom
- Drill file
- Drill legend
- FAB outline (dimensions, special features)
- Netlist file

The special features included in the FAB outline include but are not limited to notches, cutouts, bevels, back-filled vias-in-pad (used for BGA-type IC packages that have an array of pins under the device), blind/buried vias, surface finish and leveling, hole tolerances, layer count, and more.