Phil, I wonder if you are being told that these BGAs can't be used under the assumption that something else in the design can't change. For example, spacing is going to be affected by pad size. If you assume too large a pad size, then you could violate spacing requirements. PCB vendors also 'grow' patterns to account for the etching process, and that 'growth' amount increases as the copper thickness increases. So for some thickness of surface copper, 1.0 or .8 mm pitch parts are probably not possible, because the amount of 'growth' required causes the circuits to overlap. Spacing will also depend on the routing method. Are you surface routing the traces from BGA pads, or do you have via-in-pad? Surface routing will certainly eat up more room. Ben -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Bavaro Sent: Wednesday, April 11, 2012 7:27 PM To: [log in to unmask] Subject: EXTERNAL: [TN] 1.0 and 0.8 mm Pitch BGAs cannot meet Class 3? I am being told that it is not possible to layout a BGA for IPC-6012 Class 3 if the pitch is 1.0 or 0.8 mm. I am not a board designer but this doesn't sound right to me. I had a lot of experience with BGAs at 0.5 mm pitch but that was always with Class 2 requirements. Is anyone laying out PWBs with 0.8 mm pitch BGAs and still meeting Class 3 for spacing? ------------------------------------------------------------------------------ This message and any attachments are solely for the use of the addressee and may contain L-3 proprietary information that may also be defined as USG export controlled technical data. If you are not the intended recipient, any disclosure, use or distribution of its content is prohibited. Please notify the sender by reply e-mail and immediately delete this message and any attachments. ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________