| Author |
 Topic  |
|
|
shadders
United Kingdom
224 Posts |
 Posted - 05 Feb 2010 : 13:45:05
|
Hi,
I am looking for guidance as to the most appropriate method of achieving the fololowing :
1. I want to implement 2 ground planes - one digital and one analogue on the same layer - separated by digital on the right and analogue on the left (example)
2. The digital power plane above the digital ground plane.
3. Tricky bit - 4 separate analogue power planes on the same layer as the digital power plane (balanced right, balanced left and unabalanced right, and unbalanced left)
I have read some of the manual, but as this is not given as an example, i am a bit stuck.
To achieve this, will it be a copper fill approach, or can i implement two or four planes on a single layer through another faster method ?
Thanks,
Regards,
Richard. |
|
|
Iain Wilkie
United Kingdom
1015 Posts |
Posted - 05 Feb 2010 : 15:58:32
|
Simply create your planes are poured copper...very simple ... very safe. You can do your layout with or without the pours ... just drop vias when you want to pick up a plane and ignore the power nets.
Iain
|
 |
|
|
Peter Johnson
United Kingdom
498 Posts |
Posted - 05 Feb 2010 : 16:07:11
|
If you're autorouting, create the copper pour areas, and edit their properties to link them to the right nets, but don't pour them. The autorouter will recognise the potential fill and leave any tracks of the matching net as rubber bands within the fill area.
When you've finished and poured the copper, run [Tools], [Optimise Nets]. Any remaining unrouted connections are ones that need attention. |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 05 Feb 2010 : 16:50:07
|
Hi Iain, Peter,
Thanks for the replies.
So in creating copper pour areas - can these be on the same plane as a specified power plane in the Technology Files ?.
Essentially, if i have used the provided 2sig2pwr technology file, do i change the ground plane to become 2, one analogue, one digital, and use the power plane to become 1 digital and 4 analogue separate planes ?
My concern is that i am changing the technology file layer description/use such that in the end, i might as well use a 4sig technology file.
Thanks.
Regards,
Richard. |
Edited by - shadders on 05 Feb 2010 16:51:13 |
|
|
|
Iain Wilkie
United Kingdom
1015 Posts |
Posted - 05 Feb 2010 : 18:31:45
|
Not sure what is in that technology file ... I don't have it. But basically you DO NOT set any layer to POWERPLANE. Simply create the layer and set it for no tracks. Then create your copper pour areas on these layers and set them to be on the nets you wish them to support (eg. +5v).
As Peter said if you are using Pro-Router .. do the pours, then un-pour and auto-route, stubs will formed to create the palne connections. If manually routing just create stubs as necessary and end on a via
Iain |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 05 Feb 2010 : 20:17:06
|
Hi Iain,
I am not sure what is in the technology file - it came with Easy-PC.
If i am not to set a power plane, then i will not be able to use this technology file.
I have Pro-Router, but currently only using Easy-PC router. So i will probably attempt what Peter has said later - just getting to know the package at the moment for this area.
Thanks for your help - much appreciated.
Regards,
Richard. |
|
|
|
Iain Wilkie
United Kingdom
1015 Posts |
Posted - 05 Feb 2010 : 20:55:07
|
Once you have loaded a new design and a technology file you can alter this in any way you want... add more layers if you want etc etc. Just go to the design technology and change anything that is not the way you want it. In your case here if the layers you want for your planes don't exist then simply create them and mark them as "no tracks" and do not enter a net name. Then create these planes as explained above.
A technology file is only a quick way of setting up a whole load of parameters that suit any particular layout .... once loaded into a design you can change everthing around at will. You can also create your own technology files fron scratch or even by saving it from a current layout.
Iain
|
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 08 Feb 2010 : 01:04:54
|
Hi Iain,
Thanks - have created new layers. I used the 2sig2pwr technology file that came with Easy-PC, and deleted the 2 power plane layers. Created my own layers and saved the technology file. Have created 4 power planes so far - on two layers. Since i am using Op-Amps the +ve and -ve supplies for the unbalanced and balanced sections take quite a bit of time to create, but it seems to be working as expected.
What is the best way to provide power routing which has to cross over ?.
(that is positive power to the left and right section, and negative power to left and right also - i was going to use the bottom layer for the connection for the negative, and top layer for the positive - using manually created vias - would this be the best approach ?) Thanks for you help on this, much appreciated.
Regards,
Richard. |
Edited by - shadders on 08 Feb 2010 01:06:16 |
|
|
|
Peter Johnson
United Kingdom
498 Posts |
Posted - 09 Feb 2010 : 09:53:23
|
Essentially a technology file is just a stripped down design. You can open them like a normal design file, edit the settings, and save them under a custom name. When you create a new file you're given the opportunity to choose which technology file is used, though Easy-PC always offers the last used one.
Similarly, you can choose the technology file used for symbol editing by using the [Tech Files] button off the relevant tab in the library manager. |
Edited by - Peter Johnson on 09 Feb 2010 10:02:11 |
|
|
|
Peter Johnson
United Kingdom
498 Posts |
Posted - 09 Feb 2010 : 10:01:21
|
There are some issues with copper pour. It's the right solution for split planes, but it really doesn't work well on a layer designated as a power plane. That gives a problem with autorouting. EasyRouter will only accept two routing layers, and some ProRouter licences are the same. That means that you HAVE to use power planes to get enough layers.
The compromise is to temporarily create as many power planes as you need to assign one to each power net. Route the board, then delete all the extra power plane layers, except for ones you will need to hold the copper pour. As Iain says, set the net name on these to ''none', then you'll be able to reassign the bias to 'No Tracks' instead of 'Power Plane'. After that it's straightforward adding the copper pour areas and linking them to the relevant nets.
After you've poured the copper, run a connectivity check. That will make sure that all the extra vias added by the autorouter really do fall within the correct copper pour boundaries. If not, you may have to tweak a few profiles! |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 09 Feb 2010 : 14:05:32
|
Hi Peter,
Thanks for the reply. I think i understand it all 
To recap - i have determined that i will have 2 ground planes on one layer, and 14 power planes on one layer - small.
I set the inner layers (2 layers) to electrical - since i did not think you could have more than a single split plane - that is, two segments maximum.
1. Is there a layer preference that Easy Router uses such as top and bottom only ?
2. I have set the two inner layers to "no tracks" - so this will stop routing on those layers - hence does this suffice question number 1 - Easy Router will only route top and bottom ?.
3. Can you have more than 2 segments to a split plane ?.
4. I have pro-router - 4 layers - will this be the optimal router for the 14 power segments on one layer, and 2 ground segments on the other inner layer ?
Apologies for the novice questions. Thanks.
Regards,
Richard. |
Edited by - shadders on 09 Feb 2010 15:35:33 |
|
|
|
Peter Johnson
United Kingdom
498 Posts |
Posted - 10 Feb 2010 : 14:45:29
|
Firstly, you can have as many copper pour areas as you can fit on a layer. There's no upper limit.
Secondly, Easy Router ONLY ignores a layer if it's designated as a power plane. Setting it to 'No Tracks' doesn't work. To route this Using Easy-Router would require (initially) 18 layers! (2 copper, 2 for the grounds, and 14 for the power signals). You'd then remove 14 of them after routing, leaving 2 inner plus the 2 outer tracked layers. You'd then convert the 2 inner layers to no tracks and add the relevant copper pours. Quite messy!
Since you've got 4-layer ProRouter, it's easy. Set the inner layers to no tracks, add the 16 copper pour areas, assigning the relevant nets using the properties of each one. Don't pour them. Run ProRouter, and it will recognise and use the copper pour areas. Finally, pour all the copper (which you can do using [Tools], [Pour Copper]). |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 10 Feb 2010 : 22:47:20
|
Hi Peter,
Thanks for clearing up those points, much appreciated.
Regards,
Richard. |
|
|
|
Peter Johnson
United Kingdom
498 Posts |
Posted - 11 Feb 2010 : 09:46:10
|
Easy Router will only route two electrical layers, so it will refuse to route a 4-layer board unless at least 2 of the layers are set as power planes. That means that your only option for routing the design is to use ProRouter, as you have a 4-layer license for that.
Nothing to do with the routing, but both for ease of fault finding, and best EMC performance, put your copper pour partial planes on the 2 inner layers, and leave the tracks on the outside.
There's nothing to stop you pouring both the top and bottom tracking layers with the relevant grounds as well when you've finished, (to improve the EMC performance) but leave that until last.
There is NO UPPER LIMIT to the number of segments you can have in a split plane. (I did mention yesterday putting 16 copper pours on the two inner layers). |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 11 Feb 2010 : 12:15:32
|
Hi Peter,
Thanks.
So, i can set the two inner layers to power planes, and pour copper to obtain the 14 power segments, use Easy PC Router.
Alternatively set the layers to all electrical and use Pro Router after adding the copper pour areas.
Your statement "Easy Router will only route two electrical layers, so it will refuse to route a 4-layer board unless at least 2 of the layers are set as power planes." now makes sense. I had set all layers to electrical, and attempted to route to see what happened and all nets were NC.
The pcb design is now covered with pink/red lines with NC statements - i tried unrouting all nets and it has not cleared them.
Is this permanent and can i clear the pcb layout to show the yellow nets as standard ?. Thanks.
Regards,
Richard. |
Edited by - shadders on 11 Feb 2010 12:16:27 |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 11 Feb 2010 : 21:56:36
|
Hi Peter,
"Is this permanent and can i clear the pcb layout to show the yellow nets as standard ?. " - have found the clear errors on the DRC.
Regards,
Richard. |
|
|
|
Peter Johnson
United Kingdom
498 Posts |
Posted - 12 Feb 2010 : 14:40:00
|
The lines and 'NC' labels are DRC errors, so go to [Tools], [Design Rule Check] and clear the errors there.
The yellow connec tion lines will usually tidy themselves up as the relevant connections are made in copper, but the tidy algorithm is fairly simple, so if it misses some, use [Tools], [Optimise Netsa], [All Nets] to catch the stragglers. You do need copper in place first, so only do this after you've poured.
If you still feel adrift, give the support line a call - it would be a lot faster! |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 15 Feb 2010 : 00:58:53
|
Hi Peter,
Thanks - i think i need to learn a bit of patience - this is my first detailed use of the program, so will have to take more time. Thanks again.
Regards,
Richard. |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 20 Jul 2010 : 14:31:15
|
quote:
Originally posted by Peter Johnson
Firstly, you can have as many copper pour areas as you can fit on a layer. There's no upper limit.
Since you've got 4-layer ProRouter, it's easy. Set the inner layers to no tracks, add the 16 copper pour areas, assigning the relevant nets using the properties of each one. Don't pour them. Run ProRouter, and it will recognise and use the copper pour areas. Finally, pour all the copper (which you can do using [Tools], [Pour Copper]).
Hi Peter,
Just to request a bit more help on this. I have created a copper pour area on the Top layer, set it to a Net, and in the Design Technology the Top Layer Bias has been set to X.
I ran Pro-Router and it has routed a track across the non filled copper pour area on the Top Layer.
If i then fill the coppoer pour area and Optimise Nets, will this then re-route the track on the top layer that has previously been routed across the copper pour area ?.
If i am to add holes with ground connectivity for the PCB screws and pillars, will i have the same problem ?.
Thanks and regards,
Richard. |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 20 Jul 2010 : 17:22:05
|
Hi,
I had a play - i filled the Top Layer copper pour and then routed using the Pro-Router - seems to have routed the previous top layer routes onto the bottom layer.
Hence i assume the answer will be pour top and bottom layer copper areas before routing.
The Pro-Router is very fast and completes as expected in a short time period - so clearing and re-routing is not a problem.
I expect that the scrw holes for PCB pillars will be the same - any copper area filled and assigned a net before routing ?
Regards,
Richard. |
|
|
|
shadders
United Kingdom
224 Posts |
Posted - 04 Aug 2010 : 22:47:00
|
| > |
Edited by - shadders on 05 Aug 2010 03:56:38 |
|
|
| |
Topic |
|
Novice Question - PCB Power Planes