OrCAD Capture to Allegro PCB conversion

Thread Starter

Darren Holdstock

Joined Feb 10, 2009
Has anyone done this successfully? Our in-house schematic capture tool is OrCAD Capture 16.2, and up until recently this has been imported into OrCAD Layout for the PCB. However, we've just changed to a different PCB design house, and unfortunately they use Allegro. For the first set of boards they took the OrCAD netlist, manually edited it, and then imported that into Allegro. For the footprints they either manually shoehorned in their own library files or translated our custom footprints, one by one, from the Layout .MAX files especially created for just one footprint.

Major issues now arise because we have to feed the PCB design house extensive changes for the next board iteration. They want to have us send them marked-up paper schematics and they'll then manually edit the netlists. I, however, am sweating spinal fluid at the prospect of this. I'm unhappy to relinquish control of the master schematics, and I'm certain this sloppy translation method will lead to errors that will be difficult to find. Also, this will mean the PCB designers won't be able to run a DRC, and as the boards are very complex this strikes me as sheer negligence.

I've done a bit of research on the process, and thus far this is what I think needs to be done:

  1. The OrCAD Capture net names need to be edited so that they are legal with respect to Allegro (no special characters, truncated length).
  2. The PCB footprint names in Capture need to be changed to the names of the relevant footprints in the Allegro library.
  3. Ensure there are no illegal or missing footprints, as apparently Allegro will reject the lot if even one item is wrong.
  4. The net design rules (e.g. track width and clearance) should be set in OrCAD and then Allegro will import them as "Allegro Extended Design Rules".
I don't like back annotation anyway, so I'm not too worried about that. Any changes can be forward-annotated from the master OrCAD schematics.

The PCB designers assure us that their current method is the only translation route, but I don't believe this at all. Has anyone got any hints here? All tips gratefully received.