Beyond the Board: What Companies Need to Know Before Entering the MilAero PCB Market
Defense Speak Interpreted: If CHIPS Cuts Back, What Happens to Electronics Packaging Funds?
American Made Advocacy: Where’s the Budget for a Modern Military Run on Microelectronics?
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:
Testimonial
"We’re proud to call I-Connect007 a trusted partner. Their innovative approach and industry insight made our podcast collaboration a success by connecting us with the right audience and delivering real results."
Julia McCaffrey - NCAB GroupSuggested Items
Beyond Design: Slaying Signal Integrity Villains
09/17/2025 | Barry Olney -- Column: Beyond DesignHigh-speed PCB design is a balancing act, where subtle oversights can develop into major signal integrity nightmares. Some culprits lie dormant during early validation, only to reveal themselves later through workflow disruptions and elusive performance bottlenecks. Take crosstalk, for example. What begins as a stray signal coupling between traces can ripple through the design, ultimately destabilizing the power distribution network. Each of these troublemakers operates with signature tactics, but they also have well-known vulnerabilities.
Polar Instruments Announces Additive Transmission Line Support for Si9000e
08/20/2025 | Polar InstrumentsTransmission lines embedded into the PCB surface are a feature of UHDI constructions. The 2025 fall release of Polar's Si9000e PCB impedance & insertion loss transmission line field solver incorporates eight new single ended, differential and coplanar transmission line structures.
I-Connect007 Editor’s Choice: Five Must-Reads for the Week
05/30/2025 | Andy Shaughnessy, Design007I don’t have a scorecard, but I do have a weekly wrap-up of must-reads that I think deserve another “bite of the apple,” so to speak. IPC’s Rich Cappetto shares his perspective on everything from tariffs to the CHIPS Act. Columnist Josh Casper discusses the use of AI in 3D AOI systems and the immediate benefits that AI can bring about. Columnist Anaya Vardya explains how technologies like AI can improve our customer service, as well as our manufacturing processes.
Connect the Dots: Proactive Controlled Impedance
05/29/2025 | Matt Stevenson -- Column: Connect the DotsFrom data centers to smartphones, designers know that the ohms have it. Getting impedance right ensures all-important signal integrity and delivers high-performing boards. Our designers understand the importance of controlled impedance, but not everyone addresses it in their designs. The most common and important controlled impedance types we see include microstrip, stripline, embedded microstrip, and differential pairs.
Designers Notebook: Layer Stackup Planning for RF Circuit Boards
04/17/2025 | Vern Solberg -- Column: Designer's NotebookWhen designing multiple layer circuits requiring impedance control, the circuit board designer will work closely with an engineering specialist cognizant of RF printed circuit board design and layout, including mixed-signal applications.