http://www.eurocircuits.com/images/stories/ec09/ec-design-guidelines-englsi= h-1-2010-v3.pdf Above link is to a set of PCB guidelines by Eurocircuits. May form a useful= further study document for the OP. --=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 .