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March 2015 • The PCB Design Magazine 29 Having done it right so far, this is no time to lose your nerve. The first pass of the design layout may not produce the perfect result. Let's imagine the post layout simulation reveals we have SI issues with 90 differential pairs of the 2,000 that we have used. This leaves us two choices. The hard way—fix them by individual review or the easy way—add four more layers dedicated to the 90 pairs. Clearly the hard way is the better way, but that takes time and that time requires skills, not just machines. This is where good designers stand out and can really earn their money. All too often the easy way is chosen, more layers are added, a materials upgrade is chosen with better performance and higher costs, often in the order of 15–25% are added. In the case of our example, the hard way resulted in a board meeting the 36-layer target that fits mechanically and is easily manufactur- able at the target cost of $1,200. The easy way delivered a 42-layer board, with a less readily available materials, which is harder to manufac- ture, costs $1,550 and impacts on other parts of the mechanical design, having impacted on board thickness. The right way is undoubtedly the harder way, and the results will be savings enjoyed throughout the life of the product, greater re- liability, more manufacturing flexibility and a real sense of satisfaction in getting it right. Choosing a laminate is important, choos- ing a laminate supplier is even more important. A supplier or distributor can provide you with what you ask for, but a laminate partner will provide you with design and fabrication sup- port throughout, helping you get it right first time. PCBDESIGn feature MAkE ThE RIGhT DECISIOnS AT ThE RIGhT TIME In ThE PCB DESIGn PROCESS continues Martin Cotton is director of oeM technology for ventec international group. realtimewith.com CliCk To View Video Interview leo lambert, vice president and technical director of ePTAC, sat down with Andy shaughnessy to discuss ePTAC's latest expansion, which includes iPC's certified interconnect designer (CiD) curriculum. EPTAC Expansion Includes CID Curriculum by Real Time with... IPC APEX EXPO 2015