--- In si-list@xxxxxxxxxxxxxxx, steve weir <weirsi@xxxx> wrote: > ... I would be quite hesitant to > leave a solid plane unbalanced. > Since you have options that will > not otherwise impair your design, > I would employ them. OK, if I swap the layers as you suggested, from the top down I have: top copper, mainly breakouts, not much routing ground plane power plane (large layer spacing here, others small) internal routing ground place bottom routing and the problem is that the power plane isn't balanced by another solid plane. As the layer that is opposite to it is one of my two routing layers (assuming, as you said, I won't get much routing done on the top, which is, in any case, referenced to a different plane) I can't do much with that and still hope to route the board. It looks as if my main option is to not have a solid power plane at all but break it up sufficiently to avoid board warpage. Another option might be to have a power plane but no ground plane near the top of the board. In both cases, I lose the embedded capacitor and exacerbate power distribution problems. I'm not sure I can see a way out of this. Graham. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu