3.2.8. Documentation Layer

The layer Top Documentation should be used to draw the most important details of the package’s appearance. It could be considered as an alternative to the 3D model of a package. But in contrast to the 3D model, the documentation layer is visible in the board editor while layouting the PCB.

Following things should be placed on the documentation layer:

• The package’s exact outline. Attention: The outer edges of the lines should correspond to the package’s edges, not the middle of the lines! So, for example if the body is 5x5mm and the line width 0.2mm, you have to draw a 4.8x4.8mm rectangle.

• The top view of the leads/legs: The leads or legs of both THT and SMT pads should be drawn from the top view, i.e. the vertical projection of them. This is needed to make packages look realistic on the documentation layer, as leads and legs are an important part of the appearance of packages.

• The contact area of SMT leads: The area where SMT leads touch the copper land pattern should be drawn as filled polygons with a line width of 0mm. This helps the PCB designer to see the expansion of the land pattern, i.e. how much copper is around the actual lead.

Example 7. Documentation layer examples (only documentation and copper layers shown)