It largely depends on the product. Normally 2 to 3 relayout is the norm in my company. That means before we order board from approved vendor, we need to have 2 to 3 prototype PCBs from fast non-approved vendors. And before that, I usually have working hard-wired board. My first design in the company was a level sensor and it failed almost all EMC tests and it took me three months and 4 relayouts to solve the problem. I believe Bob is doing more advanced stuff so it is quite possible 7-8 versions are required. Space constraint and mechanical constraint as well as EMC are the major factors for us. For product needs approval, standard compliance is also a major issue. I hear that some of the high-end flex PCB can cost more than thousand bucks in the prototype stages. It will be quite costly to have several iterations of PCB designs. Regards, Xiaofan On 10/3/05, Olin Lathrop wrote: > > Bob has apparently had different experiences than I. I see about half that > as the norm. Usually only one respin is needed to get the circuit and board > just right. The extra respins are due to inevitable requirement changes as > the product plans evolve. This has much more to do with how much the > company knows what they are doing and how well they manage the new product > process than correcting design errors. > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist