Richard, thanks for the recomendations. I guess I will work with the standard 10 mil hole via size as well.
____________ Brian G. ----- Original Message ----- From: "Richard Sumner" <[EMAIL PROTECTED]> To: "Protel EDA Discussion List" <[email protected]> Sent: Wednesday, June 21, 2006 6:59 PM Subject: Re: [PEDA] First BGA design with blind-buried vias. > Brian, > > As I said, my board is old technology, except for the bga. I used 6 > layers, top, bottom and one internal wiring, one ground (not split) > and 2 power planes, split to handle my 7 different power sources > (fpga took 3 by itself!). And only ordinary thru vias, 10 mil > finished, not tented. 30 ga ww wire fits in a 10 mil hole (not every > board us perfect on the first rev), and the vias make nice test > points. I did bring several unused fpga pins out to vias, to use as > test points to probe inside the fpga (you have to compile what you > want it to show, but the change, compile, reload and test cycle can > be as short as 10 minutes). > > Richard > > > At 05:50 PM 6/21/2006, you wrote: >>Richard, you basically hit the strategy I was working toward. >> >>I guess my question would bettee be how to configure the signal layer >>pairs >>in 99se & any other size/optimal settings regrading blind/buried vias. >> >>____________ >>Brian G. >> >> >> >>----- Original Message ----- >>From: "Richard Sumner" <[EMAIL PROTECTED]> >>To: "Protel EDA Discussion List" <[email protected]> >>Sent: Wednesday, June 21, 2006 5:08 PM >>Subject: Re: [PEDA] First BGA design with blind-buried vias. >> >> >> > Brian, >> > >> > I'm currently debugging a 6 layer board with a 676 pin bga. I >> > actually needed only 316 of the i/o pins, and I simply avoided the >> > deep rows of the bga. With only 1 trace between bga pads, I can get >> > the first two rows (counting from the outside in) on the top layer, >> > and using thru vias I can get the next two rows (equivalent, you have >> > to avoid blocking the planes with adjacent clearance around the vias) >> > on the bottom (or any other layer). This is a low volume product, not >> > very (parts) cost sensitive, so I can justify the larger package >> > (It's actually a trade off with a more expensive board). It was my >> > first board with ad2004, and I did make use of the fpga pin swapping >> > (much easier than with 99se, but still not simple) >> > >> > Richard >> > >> > >> > At 04:14 PM 6/21/2006, you wrote: >> >>Ok, I'm still using P99SE. >> >> >> >> I need to upgrade an existing project with the main IC being a 240 >> >> QFP, >> >>going to an Altera 484 pin, 1mm fineline BGA, however, there are some >> >>parts >> >>under the chip. >> >> >> >> My PCB is only 6 layers. I've never done blind/buried vias before >> >> in >> >>protel. How should I configure protel to handle the blind-buried vias >> >>under >> >>the BGA pads. Am I attempting something that shouldn't be done? Can >> >>some >> >>BGA pads just be pads with no holes at all without upsetting the >> >>mounting? >> >>Is there any good reason to switch to microvias? >> >> >> >> >> >>____________ >> >>Brian G. >> >> >> >> >> >> >> >>____________________________________________________________ >> >>You are subscribed to the PEDA discussion forum >> >> >> >>To Post messages: >> >>mailto:[email protected] >> >> >> >>Unsubscribe and Other Options: >> >>http://techservinc.com/mailman/listinfo/peda_techservinc.com >> >> >> >>Browse or Search Old Archives (2001-2004): >> >>http://www.mail-archive.com/[email protected] >> >> >> >>Browse or Search Current Archives (2004-Current): >> >>http://www.mail-archive.com/[email protected] >> > >> > Cheesecote Mountain CAMAC, 24 Halley Drive; Pomona, NY 10970 >> > voice: 845 364 0211, NEW fax: 877-840-0023, Skype: cmcamac, >> > www.cmcamac.com >> > >> > ____________________________________________________________ >> > You are subscribed to the PEDA discussion forum >> > >> > To Post messages: >> > mailto:[email protected] >> > >> > Unsubscribe and Other Options: >> > http://techservinc.com/mailman/listinfo/peda_techservinc.com >> > >> > Browse or Search Old Archives (2001-2004): >> > http://www.mail-archive.com/[email protected] >> > >> > Browse or Search Current Archives (2004-Current): >> > http://www.mail-archive.com/[email protected] >> > >> >> >> >>____________________________________________________________ >>You are subscribed to the PEDA discussion forum >> >>To Post messages: >>mailto:[email protected] >> >>Unsubscribe and Other Options: >>http://techservinc.com/mailman/listinfo/peda_techservinc.com >> >>Browse or Search Old Archives (2001-2004): >>http://www.mail-archive.com/[email protected] >> >>Browse or Search Current Archives (2004-Current): >>http://www.mail-archive.com/[email protected] > > Cheesecote Mountain CAMAC, 24 Halley Drive; Pomona, NY 10970 > voice: 845 364 0211, NEW fax: 877-840-0023, Skype: cmcamac, > www.cmcamac.com > > ____________________________________________________________ > You are subscribed to the PEDA discussion forum > > To Post messages: > mailto:[email protected] > > Unsubscribe and Other Options: > http://techservinc.com/mailman/listinfo/peda_techservinc.com > > Browse or Search Old Archives (2001-2004): > http://www.mail-archive.com/[email protected] > > Browse or Search Current Archives (2004-Current): > http://www.mail-archive.com/[email protected] ____________________________________________________________ You are subscribed to the PEDA discussion forum To Post messages: mailto:[email protected] Unsubscribe and Other Options: http://techservinc.com/mailman/listinfo/peda_techservinc.com Browse or Search Old Archives (2001-2004): http://www.mail-archive.com/[email protected] Browse or Search Current Archives (2004-Current): http://www.mail-archive.com/[email protected]
