Stats

  • Locked Locked
  • Replies 4
  • Subscribers 166
  • Views 2535
  • Members are here 0
More Content
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Thermals positive planes, negative planes I'm confused

stellar

In Layout planes were always negative. I'd like to use positive planes on the present board but I don't see any connectivity on the artwork where there should be. I've defined my via as a 10mil drill with 30mil regular pad. For thermal relief I have a flash symbol defined for inner layers and my antipad is 50mil. When I set the layers to negative I see the thermals correctly. for positive planes do I need to define the inner thermal relief as a pad instead of a flash? Also if I can succeed in learning how to use positive planes I'd like no thermals on vias at all just flooded. I don't like the missing spokes and don't think thermals are necessary on vias.
  • hpattie

    You will need to set up your Dynamic Shape Parameters. This can be done either Globally (all planes), or Locally (individual plane).

    Under Shape, click on the Global Dynamic Parameters tab, and then the Thermal relief connects tab. This is where you can set your vias to full contact, and set the thermal width for pins. On the Clearances tab, I advise setting an oversize value of .2 to avoid DRC errors.

    Regards,

    Harold Pattie C.I.D.+

    harold.pattie@ericsson.com

  • stellar

    It seems that you have to set the Global Dynamic Parameters for full contact plus at Artwork creation also check another box for thermal full contact. I think after doing both I'm seeing the vias flooded but don't like this if true because during routing I want to see some contact indicator and if true you have to remember to enable both before generating artwork else the planes won't have connection. I thought I read that the artwork generation full contact box superceeds the Global Dynamic Parameters setting so you can see a thermal during design but will test this again to be sure.
  • stellar

    Yes it does appear you have to have the global dynamic set to full contact and the artwork via thermal option set to full contact to flood them on a positive layer. During routing there are no visual cues that a connection is made. I hope I'm totally mistaken on this and there are some other settings to be deal with.
  • steve

     

    The Full contact thermal reliefs in the artwork settings only apply to negative artworks. (have a look at the help button on the manufcature - artwork from).

    Just set the global dynamic parameters and you get the connections you require. Once a connection is made the ratnest disappears. If you are using GND or VCC you might not see a ratnest. Have a look a Constraint Manager - Properties - Net - General Properties. There is a no rat property which by default is set for the above two nets. Just clear that and you will see them again.

Cadence Guidelines

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.