Innovative Signal Integrity & Backplane Solutions
During DesignCon 2025, I had several side discussions about the findings presented in my DesignCon 2024 paper on dielectric anisotropy. A key concern raised was the discrepancy between measured results and simulations when converting the out-of-plane dielectric constant (Dkz) to in-plane Dkxy using my heuristic method. While Isola’s Tachyon 100G showed an average material anisotropy [ ]
Also Published in Signal Integrity Journal December 17, 2024 Figure 1 Comparison of NRZ (PAM-2) encoding versus PAM-4 encoding (A) and respective eye diagrams (B). To keep up with the bandwidth demands of the industry, non-return-to-zero (NRZ) signaling has been replaced by pulse amplitude modulation level-4 (PAM-4) signaling. To maintain the same naming convention, NRZ [ ]
Originally published in Signal Integrity Journal March 20, 2024. As artificial intelligence (AI) and machine learning (ML) challenge engineers to process more data faster, electronic design automation (EDA) tools are progressively integrating AI and ML to advance the design process. Many refer to this process as “shifting-left” or “shift-left.” Several EDA tools often boast about [ ]
Fiber weave effect (FWE) skew, also known as glass-weave skew (GWS), is becoming more of an issue as bit rates continue to soar upwards. Today’s 56GB/s is state of the art in high-speed routers and 112 GB/s is just around the corner. While next generation PCIe, used in the personal computer and server industry, is [ ]
Originally published Signal Integrity Journal March 20, 2023 I often get asked by young engineers what it takes to become a good SI/PI or EMC engineer. I quickly respond with, “What’s on your bookshelf?”, because I’m a firm believer you can never learn too much on a particular subject. So answering the same question about [ ]
Originally published Signal Integrity Journal August 9, 2022 When two coplanar parallel traces running in close proximity over the coupled length, as shown in Figure 1, they are electromagnetically coupled together. When two complementary signals are transmitted, there is mutual electromagnetic coupling defined by the amount of mutual inductance and capacitance. This is known as [ ]
To avoid “garbage in, garbage out” (GIGO) with any field solver, first you need to understand the little nuances of PCB fabrication process and how to interpret manufacturers’ data sheets. But most importantly you need to understand the tool’s user interface and what it is asking for. All 2D or 3D field solvers will give [ ]
Originally published in Signal Integrity Journal, May 31, 2022 In part one, “A Tale of Two Data Sheets”, I explained how air entrapment, due to IPC-TM-650-2.5.5.5 test method manual [7], is the primary reason for effective dielectric constant (Dkeff) and phase delay discrepancies between simulation and device under test (DUT) measurements. Entrapped air of the [ ]
Originally published SI Journal April 26, 2022 When doing printed circuit board (PCB) stackup and signal integrity (SI) impedance modeling, we need to get the dielectric material properties from the right sources. One important parameter for accurate impedance modeling is relative permittivity (εr) of the dielectric material, otherwise known as dielectric constant (Dk). The best [ ]
This article is an edited version of White Paper, “Heuristic Modeling of Transmission Lines due to Mixed Reference Plane Foil Roughness in Printed Circuit Board Stackups” [1]. Designing the right printed circuit board (PCB) stackup can make or break your product performance. If your product has circuitry that is transmission loss sensitive, then paying attention [ ]