SIMULATION Field Solvers for Transmission Line Analysis: How Similar Are They? An essential element in circuit board design is engineering the stackup to achieve specific transmission line properties, like characteristic impedance and crosstalk. The best tool for this is a field solver, either a 2D or 3D. But with so many commercially available, the question is always which one to use? A study of six commercial field solver tools evaluates the relative precision and compares their predictions. by Gaurav Narula and Dr. Eric Bogatin
HOLE RELIABILITY Conductive Inks vs. Nonconductive Inks for Via Fill Just 15 years ago, filling a via was considered a specialty process limited to a small group of product applications and almost exclusively to one material: conductive ink. Today, many nonconductive inks are superior in performance, and much less expensive, than their conductive cousins. by Roy Akber
RETROSPECTIVE In Memoriam A look back at friends and colleagues who left us in 2015. by Mike Buetow
SIGNAL INTEGRITY Copper Roughness Electromagnetics 101 Most electrical engineers working with high-speed differential interfaces such as PCIe are aware of the effect of rough copper on insertion loss – and know it is to be avoided. What they may not understand is exactly why that’s true. Why smoothing copper for better signal integrity could degrade mechanical performance. by JeFF Loyer
SCHEDULING A Layout Time Estimating Tool Necessity is the mother of invention. How that, plus insistent engineers, led to an algorithm for design scheduling. by James Jackson
CONFORMAL COATINGS Competitive Analysis of Parylene Coatings Based on Metrology A study comparing the quality and performance of four Parylene C coatings investigated whether variations in surface roughness, contact angle, and crystallinity values affect environmental protection performance. Despite differences in the coatings, similar results were seen throughout. by Sean Clancy, Ph.D.
THE FUTURE Electronics 2020: What Will the Industry Look Like? Robots, DNA-based circuits, 3D printers, supply chain migration: These are just some of the challenges – and opportunities – the electronics industry is facing today. What leading electronics experts see in the design and manufacturing landscape the next several years. by Mike Buetow
THERMAL MANAGEMENT How Hot Is My Via? (Cooler Than You Think!) Simulations of via thermal excursions make clear designers have been overestimating what the size of a conductor must be to handle a given current. In fact, most designers don’t have any idea how hot a via gets. But it is not the current that determines the via temperature. Rather, the via temperature is determined (generally) by the conductor temperature. by Douglas G. Brooks, Ph.D. and Johannes Adam, Ph.D.
DfM Refining Lean NPI at Optimum Design Associates The third phase of a multi-year study of the implementation of Lean NPI at a small-tier EMS reveals that moving DfM earlier in the process catches errors sooner than ever before, allowing them to be quickly and inexpensively rectified. by Randy Holt
PCB DESIGN PCB Fusing Currents What if a trace normally carries a nominal current, but then, under catastrophic failure conditions, is subject to a severe overload? How big does a trace need to be? by Douglas G. Brooks, Ph.D. and Johannes Adam, Ph.D.
SALARY SURVEY PCB Design Industry Thrives While in Need of New Recruits Nearly 500 respondents around the world – our largest response yet – report greater compensation levels (and more gray hairs). But what else we learned this year may surprise you. by Chelsey Drysdale
COVER STORY China in Charge The winners in 2014 in terms of revenue gains were flexible circuit manufacturers that built for Apple, but the annual NTI-100 ranking of the largest board fabricators reveals a quiet but steadier trend: the emergence of the domestic Chinese players. by Dr. Hayao Nakahara
PLATING Acid Gold Plating Bath for PCB Connectors The winners in 2014 in terms of revenue gains were flexible circuit manufacturers that built for Apple, but the annual NTI-100 ranking of the largest board fabricators reveals a quiet but steadier trend: the emergence of the domestic Chinese players. by Dr. Hayao Nakahara
MENTOR GRAPHICS How Change Might Bring More Predictability at Mentor Graphics Over 30 years ranging from Digital Equipment to some of the top PCB software vendors, A.J. Incorvaia has honed his knowledge of software development but also how customers think and work. by Mike Buetow
FLEX DESIGN Designing a Successful High-Speed Rigid-Flex PCB How do you determine what’s more important: high-speed signal integrity or the flexibility of the circuits? by Ben Jordan
CAD TOOLS 3D Multi-board Product-Level PCB and IC Packaging Design A new generation of tools manages multi-board placement in both 2D and 3D and enables co-design of the chip, package and board in a single environment. by Craig Armenti
PCB DESIGN Who Were Preece and Onderdonk? IPC-2152 was a major step forward in helping designers deal with current carrying capacity. But sometimes there is a power handling issue that falls outside the scope of IPC-2152. What we can learn from the first known research of the limits of copper conductors. by Douglas G, Brooks, Ph.D. and Johannes Adam, Ph.D.
THE PROFESSION PCB Designers ‘Flying the Plane’ The future of PCB designers isn’t just on the minds of those in the trenches; it’s also becoming part of the discussion at CAD vendor user group conferences. How one major OEM is attracting new blood to the design profession. by Chelsey Drysdale
BASE MATERIALS Microsectioning of Laminates Microsectioning can be an extremely useful technique to inspect PCBs. However, incorrectly prepared samples can lead to wrong interpretation of the results. The best process is tailored for the components of the laminate or the boards. by Karin Rudman Prieto, Ph.D., Peg Conn, Lizabeth Lagos and Charles Lehmann