Data Sheet

PCB Layout
117
Our board is not likely to be complex enough that this will be an issue but we'll set the neck style
to 15th so that we can practice.
Given that we don’t really have current constraints the choice of vias is a tradeoff between the
higher manufacturing costs of smaller vias and the decreased routing quality of large vias. For
the current this circuit is dealing with and for a standard 1.6mm FR-4 support plated with 35um
copper, vias with the standard 0.4mm hole are a good compromise. For the power tracks we
need a suitable annular size and 40
th
is a reasonable choice. We can therefore set the via style
to be V40.
If you are not sure of the characteristics of a particular style, you can view them by
selecting the appropriate mode icon (via, track, pad, etc.), highlighting the style in
question in the Object Selector, and then clicking on the ‘E’ button at the top of the
Object Selector.
The options at the bottom of the dialogue form allow us to change the via type (clearly not
relevant on a two layer board) and also to change the colour or visibility of the ratsnest lines.
The latter can be useful if we are manually routing and wish to quickly distinguish between
power and signal connections.
The layer assignment pairs on the right hand side tell the autorouter which layers to route on for
multi-layer boards. Again, for our two layer board, there is nothing to configure here.
We should now have finished setting up the POWER net class – your dialogue form should now
be configured as per the following screenshot.
Specifying the Power net settings