robertferanec , 09-04-2017, 11:40 AM
Here are the cases where we use the polygons most:
- We use polygons mostly on power rails. This means, ideally you would like to have GND as one big polygon / plane under you whole PCB. Then, you may want to create local polygons for local powers under the components using that specific power.
- Also, you may want to use polygons on the tracks which are going to carry high currents.
- Other option is to use polygons to cool down some components (e.g exposed pad connected to a big polygon ... the heat from component can be transferred through the exposed pad to the polygon cooper and the big area of polygon copper helps cool down the component)
However, be careful with nets which are running high frequencies and are connected to polygons - wrongly used polygons can make your EMC/EMI worse.