Defense Speak Interpreted: It’s Time for a ‘Defense-Speak’ Update
Beyond the Board: The Future of Innovation—Why the Electronics Industry Needs You
American Made Advocacy: New Congress, New Opportunities
Pushing the Limits of PCB Impedance Control
July 9, 2024 | Alex Knowles, RoBATEstimated reading time: 1 minute
While we’ve long known the importance of impedance control in PCB design, with the increase in frequencies, the decrease in SNR (NRZ to PAM4), and the continual reduction in device size, the impact of signal integrity on poor impedance control of transmission lines is even more significant.
What Affects Impedance in a PCB?
Obviously, the critical elements include the design of trace width/separation, copper thickness, dielectric, stackup, glass weave, routing/snaking, and via placement. There are many helpful products to simulate and simplify this process, but theoretical simulation and experimental measurement are two different ballgames. Now we must look past our perfectly ideal design and get it manufactured.
All PCB fabricators have their own carefully guarded methods of modifying their process to achieve the desired controlled impedance specification. When you start considering the techniques and processes in PCB manufacturing, the list seems endless: etching, high layer counts, feature density, pressing, layer registration, material storage, and expansion/contraction. With so many contributing factors, who can blame them for playing their cards close to the vest?
Thus, how well can these manufacturing processes produce a match to the original design, and how well will the result match the theory? As Einstein said, “A theory is something nobody believes in except the person who made it. An experiment is something everybody believes, except the person who made it.”
To read this entire article, which appeared in the June 2024 issue of PCB007 Magazine, click here.
Share on:
Suggested Items
Beyond Design: Key SI Considerations for High-speed PCB Design
03/20/2025 | Barry Olney -- Column: Beyond DesignOver the past two decades, I've simulated numerous complex, high-speed designs for customers creating computer-based products. In addition, I've conducted signal integrity software training courses and led classes on high-speed design. In this month’s column, I will reflect on the key considerations for achieving a successful high-speed PCB design that performs reliably, and I’ll highlight some of the common signal integrity issues that I frequently encounter.
Fresh PCB Concepts: PCB Stackup Strategies—Minimizing Crosstalk and EMI for Signal Integrity
01/09/2025 | Team NCAB -- Column: Fresh PCB ConceptsPCBs are critical components in almost every modern electronic device, but their design goes far beyond routing signals from one point to another. The stackup of a PCB (the arrangement of its layers) has a significant impact on signal integrity, electromagnetic interference (EMI), and crosstalk. The complexity of these issues grows exponentially as designs increase in speed, frequency, and complexity.
Designing for Cost to Manufacture
11/21/2024 | Marcy LaRont, I-Connect007ICAPE's Richard Koensgen, a seasoned field application engineer with a rich background in PCB technology, shares his journey of working with customers and manufacturers through the intricacies of circuit board development and emphasizes the importance of early-stage collaboration with PCB designers. With a focus on tackling the most challenging aspects of PCB design and manufacturing, he discusses everything from layout considerations to the thermal challenges of today's technology when it comes to designing for cost.
Beyond Design: High-speed Rules of Thumb
11/21/2024 | Barry Olney -- Column: Beyond DesignThe idiom “rule of thumb” is often used in electronics design and has its origins in the practice of measuring roughly with one’s thumb. Rules of thumb are easy-to-remember, broadly accurate guides or principles based on practice rather than theory. They are used to help feed our intuition to find a quick solution based on experience. We are often forced to use rules of thumb in PCB design in the absence of expensive analysis tools. We also use them to get quick ballpark figures initially and then fine-tune the numbers with further analysis. We can use rules of thumb as a sanity check to assess whether we are using our tools correctly. In this month’s column, I will present some commonly used and helpful rules for high-speed PCB design.
Polar Instruments Launches New GRS200 with Extended Troubleshooting for the Repair of Electronic Assemblies
08/02/2024 | Polar InstrumentsThe new GRS200 fault locator uses the proven passive analogue signature analysis and compares a faultless assembly with the board under test. This method detects typical faults in electronics production, service and repairs quickly and without extensive circuit knowledge.