> -----Original Message----- > From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of Jon > Chandler > Sent: 29 July 2010 17:17 > To: Microcontroller discussion list - Public. > Subject: Re: [EE] Generic SMD pad layout catalogue? >=20 > On Thu, Jul 29, 2010 at 4:57 AM, Olin Lathrop wrote: >=20 > > > > I don't understand the problem. Every datasheet has detailed package > > dimensions. Workable footprints can be decided from those easily enough... > > > > >=20 >=20 > > Most manufacturer suggested footprints suck anyway. > > >=20 >=20 > Is it just me or do Olin's comments add up to less than zero? Well, I find him partly correct on this one. Often the manufacturers don't have enough length on the outside end of the pad for hand soldering, and sometimes when you work through the dimensional tolerances the inside to inside spacing to too far to get a proper fillet at the back of the leg. We have found that it does not pay to take the manufacturers data at face value, but to at least double check it. We now have a spreadsheet for calculating such things easily. --=20 Scanned by iCritical. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .