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Beyond Design: Just a Matter of Time

11/21/2023 | Barry Olney -- Column: Beyond Design
Electromagnetic energy propagates at about half the speed of light within the dielectric of a multilayer PCB. This speed is inversely proportional to the square root of the dielectric constant (Dk) of the material. The lower the Dk, the faster the propagation of the wave. In the past, we ignored the board-level delay as it was relatively instantaneous compared to the slow rise time of the signal waveform. But now that we have entered the realm of Gigabit/s design, an unaccounted 10 ps of delay can mean the difference between success and absolute failure of a high-speed design. Also, the trend is toward lower core voltages, which conserves power. However, reducing the core voltage also reduces the noise margin and impacts the system timing budget.

3D Electromagnetic Analysis

08/22/2023 | Yuriy Shlepnev, Simberian
Data rates in PCB interconnects are increasing in all signaling protocols (PCIe, DDR, GDDR, Ethernet, USB, SAS, InfiniBand, CEI, OIF, 5G). Most of those high-speed signaling standards have one-lane data rates over 6 Gbps (GT/s) and some up to 112 Gbps with signal spectrum in microwave and even millimeter wave bandwidths. Design of compliant interconnects at these data rates cannot simply rely on geometrical rules or rules of thumb. Signal distortion by reflections, dissipation and crosstalk can cause interconnect performance degradation or even failure. To avoid it, signal integrity compliance analysis and possible interconnect optimization is required.

Happy's Tech Talk #21: Embedded (Flush) Circuits

08/10/2023 | Happy Holden -- Column: Happy’s Tech Talk
In his Tech Talk series, Karl Dietz wrote several times about embedded circuits1, particularly detailing flush circuit technology and recessed circuit processes. In his column, Karl outlined two processes that have been used to produce these “flush” circuits: Imprint technology, based on the work of George Gregoire at Dimensional Imprint Technology, Inc., and circuit transfer process, based on Samsung Electro-Mechanics.

Standard of Excellence: Today’s Hottest Technology Trends

07/21/2023 | Anaya Vardya -- Column: Standard of Excellence
No matter what anyone says, printed circuit boards are the backbone of modern electronics. Without the PCB, what will the components attach to? Without advancements in printed circuit board technology, products of the future would be impossible. It is our responsibility to be there when our customers need us—today and in the future. That means recognizing the latest trends and making the most of them. Here's what I see is trending in microelectronics.

Beyond Design: Standing Waves in Multilayer PCB Plane Cavities

07/20/2023 | Barry Olney -- Column: Beyond Design
Plane cavities in multilayer PCBs are essentially unterminated radial transmission lines.  They form a transmission line that propagates electromagnetic (EM) energy within a plane cavity emanating from a feed point, within the plane, and outward in all directions. Like all transmission lines, it will reflect if not terminated. This creates standing waves—ringing. The bigger the mismatch, the bigger the standing waves, and the more the impedance will be location-dependent. As frequency and edge rates continue to increase, the impact of intrinsic electrical characteristics becomes more pronounced. AC switching currents in the power/ground planes can be very large. Under these circumstances, a plane pair acts more like a radial transmission line rather than a distributed planar capacitor.
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