Re: Best Footprint Practice for PCB123 / AVX 9276
PostPosted: Tue Jun 05, 2012 12:41 pm
I would suggest making the 8 pin part on the schematic and a footprint with 8 pins tied together using a filled polygon. But if you want to create half of the pads using polygons read on.
The only way to make this footprint with only four pins is to use polygons as pins. You would have four pins then use polygons to create the other four. Using polygons to create pads in a footprint is possible but requires more work and leaves errors on the layout that you will not be able to resolve. This footprint already requires a polygon to make the connection between pins which will result in drc, so in this case it would just make footprint creation harder. You could use 4 standard pin for the bottom row of the footprint. Then for the top row draw filled polygons for the pads. Once you have the pads in place you will need to create solder mask openings for the pads. Create filled polygons that are approximatley 6 mils larger than the polygon pads you created and move the new polygons to the top solder mask layer. Now move the mask openings into position above the polygon pads. Once you have all of the pads in place draw you silkscreen outline and save your footprint.
The only way to make this footprint with only four pins is to use polygons as pins. You would have four pins then use polygons to create the other four. Using polygons to create pads in a footprint is possible but requires more work and leaves errors on the layout that you will not be able to resolve. This footprint already requires a polygon to make the connection between pins which will result in drc, so in this case it would just make footprint creation harder. You could use 4 standard pin for the bottom row of the footprint. Then for the top row draw filled polygons for the pads. Once you have the pads in place you will need to create solder mask openings for the pads. Create filled polygons that are approximatley 6 mils larger than the polygon pads you created and move the new polygons to the top solder mask layer. Now move the mask openings into position above the polygon pads. Once you have all of the pads in place draw you silkscreen outline and save your footprint.