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Solid ground plane with ORCAD LAYOUT

Hi everyone!

I'm having problems with Orcad Layout. I've desgned a PCB for my company and I've sent the GERBER files to the factory. But the factory operator said me that the ground planes I've created on my design aren't solid planes and they must be solid planes.

My idea was to use all the unused PCB surface to make the ground tracks bigger, so they take all the space available where there are any tracks. Therefore I've place a big copper pour obstacle associated to the ground net. The result seems to be really good, I mean I can see a lot of copper areas going around the tracks.

But the factory guy said that, actually, the copper obstacles are made of thousands of little tracks (about 75000 tracks!!). So they just see a lot of tracks instead of a real copper area despite it seems a homogeneous area. But this is a problem for the PCB's machine.

Somehow I needto tell Orcad that the copper pour must be a continuous and homogeneous area.

Could you help me? I need to work out with this problem now!

Regards

Reply to
David
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David, The key question here, why is the "factory guy" telling you what he is telling you? I think there may be some confusion about his comments. You are interpretting it that the copper polygon should be solid (not drawn from individual lines) but I would bet he is calling for a solid ground plane within the board (a multilayer board design). What you have described about your design is quite normal for a lot of designs, designs use a poured polygon GND flooded over the unused areas of the design quite often. And the multitude of individual lines making up that polygon pour is quite normal also.

But why is the factory telling you what to do? Just fishing here because the relationship sounds a little funny the way that you have stated it in such limited detail. Do your GND connections make connections to all GND points without breaks? Do your OrCAD DRC checks report any incomplete routes/connections?

Do you have any controlled impedance lines called out? That could be a problem causing such a request from the factory guy. You can't have controlled impedance without a contiguous associated plane directly below or above your trace. If you have controlled impedance in this design then you obviously don't understand the requirements for impedance controlled lines and the factory guy knows you need a contiguous internal plane to achieve the impedance control for those lines.

--
Sincerely,
Brad Velander.

"David"  wrote in message 
news:cd2faf90-a1ab-4e06-8ad2-905ac91c3d81@p10g2000prf.googlegroups.com...
> Hi everyone!
>
> I\'m having problems with Orcad Layout. I\'ve desgned a PCB for my
> company and I\'ve sent the GERBER files to the factory. But the factory
> operator said me that the ground planes I\'ve created on my design
> aren\'t solid planes and they must be solid planes.
>
> My idea was to use all the unused PCB surface to make the ground
> tracks bigger, so they take all the space available where there are
> any tracks. Therefore I\'ve place a big copper pour obstacle associated
> to the ground net. The result seems to be really good, I mean I can
> see a lot of copper areas going around the tracks.
>
> But the factory guy said that, actually, the copper obstacles are made
> of thousands of little tracks (about 75000 tracks!!). So they just see
> a lot of tracks instead of a real copper area despite it seems a
> homogeneous area. But this is a problem for the PCB\'s machine.
>
> Somehow I needto tell Orcad that the copper pour must be a continuous
> and homogeneous area.
>
> Could you help me? I need to work out with this problem now!
>
> Regards
Reply to
Brad Velander

David

Another possibility is the kind of gerber's that you have created. the gerber format is basically "drag shape x from point a to point b". x can be defined in the file or in a seperate file depending on gerber type.

Orcad is really irritating in not creating a sub-directory for output files, you may have not sent him the "x" definitions.

Colin

Reply to
colin_toogood

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