The shop I use insists that the solder mask features must be at least 5 mills wide other wise you should gang unmask the pads.
Steve Meier joe tarantino wrote: > > > On Feb 2, 2008 11:23 AM, Jeffrey Baker <[EMAIL PROTECTED] > <mailto:[EMAIL PROTECTED]>> wrote: > > Nearly every major part I need for my latest project is packaged > in a QFN (or LFCSP as they call it over at Analog Devices). I'm > worried because the parts have round leads and Sunstone, the PCB > prototype shop, says they can't make radiused SMD pads. Has > anyone run into trouble with this, or are square pads OK? > > Generally speaking the .5mm-pitch QFN seems to be on the edge of > or beyond the capabilities of a proto shop like Sunstone, but > Sunstone has the best tolerances I've been able to find. > > -jwb > > > > _______________________________________________ > geda-user mailing list > geda-user@moria.seul.org <mailto:geda-user@moria.seul.org> > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > > > I have had one of the Sunstone shops build boards with QFN32 and QFN48 > as I recall. Results were pretty good. They had square-ended pads. > > -Be careful of solder resist "floaters" due to the little pieces > between the leads. Best bet is to remove all resist between pads. > -You may want to check your gerber files to see how much solder paste > will be applied and check with Sunstone to see if it is sufficient (or > too much). > > Does your pad have a large heat sink pad on the back? If so, you must > carefully construct this pad in the footprint (possibly out of > multiple squares). Again, check the paste layer. > > Joe T > > ------------------------------------------------------------------------ > > > > _______________________________________________ > geda-user mailing list > geda-user@moria.seul.org > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user