So, how you're doing for 1700+ balls where there is no room for capacitors on the side where the BGA part is soldered ? Usually could be the same distance to the supply planes to the top or to the bottom...(imagine a 12 layer board with supply planes on layers 4,5 and 8,9. On actual technology there is no other way than styffing on both sides. On 11/12/07, alan smith wrote: > Yes and yes. > > For BGA decoupling, it would be pretty ineffecient to push the caps that far from the planes and connections. If you put one part on the back, might as well put as many R and C's as you can as the process and costs are the same, for the most part. What happens is the board gets flowed twice, so larger and heavier parts shouldn't go on the back as they tend to misalign from the past thats holding it there and they end up being glued or held on...another cost added. But the small parts usually hold onto the board just fine the first run the the oven and then it gets flipped and run thru again. > > So, its two paste stencils, two flows, two times thru the pick n place. So your costs are going to be higher just from the process. Can it be avoided? Completly depends on the design and the technology being used, and how dense you are making the board. I've been doing double sided placements for more than 10 years now so its nothing that new. > > Martin Klingensmith wrote: > Is it atypical to put SMT components on both sides of a board? In your > experience is it significantly more expensive to have boards assembled > this way? > > Thanks, > Martin K > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > __________________________________________________ > Do You Yahoo!? > Tired of spam? Yahoo! Mail has the best spam protection around > http://mail.yahoo.com > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist