Who are We? Michael Ingham Michael Ingham specializes in the design and development of multilayer PCBs for RF and ultra High-Speed Digital applications. He has held engineering positions with Vitesse Semiconductor and Intel and is currently a Principle Design Engineer with Spectrum Integrity, Inc. where he primarily focuses on 10GHz to 50GHz applications. He has completed hundreds of successful designs and is often consulted with to identify and solve signal integrity issues. Michael holds BSEE from California Polytechnic University, San Luis Obispo, and a Sr. Member of IEEE. Judy Warner Judy Warner has nearly two decades of experience in the Printed Circuit Board Manufacturing Industry. She is the director of Sales and Marketing for Transline Technology, whose focus is on RF/MW and High Performance PCBs. She is an author of a current blog that is hosted by Printed Circuit Design and Fabrication and Microwave Journal websites. The blog focuses on RF/MW and High Performance PCB manufacturing.
The Problem The are gaps of knowledge and understanding that exist between Engineering, Design, and Manufacturing This is Particularly true in the area of High Performance Multilayer PCBsMost of us are not aware that these gaps exist and therefore fall into “pitfalls” that cause much needless frustration and failure!
What creates these Gaps? Many CAD Programs allow for any design to be created without regard to the “real world” viability for a PCB to be manufactured. As the software manufacturers have removed the stop-gaps, to allow for more flexibility and innovation, they have taken out the some safeguards that would prevent design engineers from unwittingly creating designs that are unfit or impractical for manufacturing. Integrative courses have been removed at Academic levels Fundamental understanding of Design and Mfg not being taught to engineers and increased demands for specialization leads to lack of exposure to design and manufacturing principles RF techniques are very different than digital design, yet digital designers are being increasingly called upon for High-speed digital and RF designs
It Starts with the Design and HighPerformance Expertise High Performance designs are not straight forward builds that rely only on the fabricator and material suppliers High Performance Expertise is needed at the design, layout and fabrication levels Synergy between disciplines is key to success
The Conundrum of theNon- Homogenous design The last decade’s evolution and emergence of high speed digital. Mixing Dielectrics (Unlike Materials) Materials
Common Pitfalls: Specifying an overrated material. The lowest loss tangent is not always the best choice! Looking at the Big Picture when selecting materials Addressing Conductive Loss Low dielectric materials are more costly, and typically more difficult to use in manufacturing
Common Pitfalls: Stack-ups that are not fit for manufacturing Knowing your pre-pregs, bond plies and cores. Variances of final product Reading the fine print on the data sheets Partnering with you Advanced Material Division Representatives and your design and fabrication suppliers
Common Pitfalls:Unbalanced Stack-ups Temperature Issues Warping Latent Problems
Common Pitfalls Unrealistic Tolerances Lack of knowledge of process capabilities and limitations, set up unrealistic expectations The benefits of partnering with your board supplier and/or layout engineers
Common PitfallsVery thin transmission lines Impedance issues Very “lossy” Manufacturing challenges