--- Dennis Saputelli <[EMAIL PROTECTED]> wrote: > > i assume you meant '99SE' ? > Yes I did mean that as matter of fact.
> the autorouter for it's time (which was not new even at that time) > actually wasn't too bad, but it certainly was not made to do BGAs > it did do a decent job at lined up rows of random wired DIPS :) > Well I have wired lots of dips with it, but it had quite a few anoying bugs in it still. In any case I'm looking at surface mount devices instead. So how does one do a BGA since it's only contact technically is the top or bottom layer. Does one employ vias near the pads or something? > i wouldn't get my hopes up about autorouting that thing > A 144 pin LFBGA is too much for it? > to do a solder mask opening smaller than the pad use a negative > expansion > That is definately helpful. > my brain is wired in mils so... > for a 40 mil pad with a 30 mil opening use > solder mask expansion of -5 mils > I'm so use to converting between the two I almost do it in my head these days. So that would be the override designation for the soldermask? (is this defined on the part or in the Design Rules... 99SE is a bit of a maze it looks like someone kept adding features to something that started small). > what is driving the 'solder mask defined' ? > i have read both pros and cons about that but everyone i know does > not do it > You mean solder mask over pad instead of mask about pad? It was mentioned in the package JTAG information so I asked. > .125mm is 4.9 mils > 5 mil trace/space is almost ordinary these days > > for BGAs depending on the pitch we sometimes need to go to 4mil trace > > 4mil space AKA 4/4 > Right FBGA is 0.8 mm which is 31.4 mils. So it's not a big deal to have such small traces anymore then? Stephen Stephen R. Phillips was here Please be advised what was said may be absolutely wrong, and hereby this disclaimer follows. I reserve the right to be wrong and admit it in front of the entire world. __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.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]
