Mike, since you are talking about high density connectors I assume you are using minimum via sizes. If so, given todays minimum hole sizes and annular rings, is it advisable to route this close to a hole? In my experience, taking into account hole position tolerance and over drilling to compensate for hole wall thickness, routing this close to 'padless' via might result in a short.
Maybe your fab house can do better, but the ones I've used need at least 5.5 mils around a via hole to prevent break out of the hole wall. This is what we use as minimum annular ring. For a decent fab yield we need at least 3 mils air gap to the nearest trace. Removing the unused via pad during layout doesn't buy us any extra routing room so I don't see any advantage in removing the unused via pad. If you are using vias with a greater than minimum annular ring, wouldn't you get the same by just reducing the annular rings on the affected vias? Mark Koitmaa TechServ At 10:15 AM 9/17/2002, Mike Reagan wrote: >One feature I would like to see in "future" releases or service packs is >removal of inner pads before processing gerber data. In other terms inner >pads would not be added to a via until a connection is made to that via. >The reason for this is for high density connectors where I am trying to >route between pad, I often get violations, when in fact the real gerber data >will have no clearance violations after gerbers are processed with removed >inner pads. This would allow proper routing in high density connectors. >The padstack for a via would automatically represent the a via the way it >really looks to the fabricator not to the designer. > >An no ,I dont want to go the way Accel did with their complicated padstacks >because then I have to spend time creating a complex stack library with >silly names. Editing vias in either PADS or Accel is time consuming, I >like being able to double click and everything about that object appears. <snip> * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * To post a message: mailto:[EMAIL PROTECTED] * * To leave this list visit: * http://www.techservinc.com/protelusers/leave.html * * Contact the list manager: * mailto:[EMAIL PROTECTED] * * Forum Guidelines Rules: * http://www.techservinc.com/protelusers/forumrules.html * * Browse or Search previous postings: * http://www.mail-archive.com/[email protected] * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
