SIGNAL INTEGRITY IS KEY TO TODAY’S HIGH-SPEED CONNECTIVITY DESIGNS
JOSHUA JACOBI, DIRECTOR OF SALES AND MARKETING, EPT MARKETING TEAM, EPT
DEFENDING AGAINST SIGNAL LOSS The types of materials present near the signal path are critical to the success of a high-speed signal. It is important to avoid cross-sectional changes in the contact material and to use material with high conductivity. The dielectric constant of a plastic material also affects signal transmission. The typical standard for phase matching throughout an interconnecting system is 85-100 ohms. Because electronic components can act both as an interference sink and as a source of interference, the proximity of sensitive components increases the risk of mutual interference. A high-speed signal can be lost through insertion loss as well as return loss. Insertion loss is the deviation(s) within the impedance curve, resulting in signal reflections. This describes the loss of a signal along the
The bar is higher than ever for high-speed performance, and PCB components have the potential to be either a great asset or an Achilles’ heel, especially if signal integrity is not given the foremost consideration while testing the design. What was previously only a problem for high- frequency applications is now encountered by hardware developers across the digital sphere due to the demanding nature of high data rates, some even exceeding 20+ Gb/s. Even in low-end applications, demand is increasing for smaller, faster, and more capable electrical components while less and less space is available on the rapidly shrinking real estate on today’s PCBs. Basic design requirements are always in play: how much space is available on the module, floating capability, the desired connection technology, the number of pins and the pin assignment, as well as overall performance requirements. The most pressing challenge is to manage these requirements successfully while avoiding the looming threat of signal loss during module operation. If the present signal paths are dampened or lost, the multitude of additional design factors can become entirely irrelevant as the components lose their ability to transmit data. For a module to work at peak operational capability, defending against signal loss must be at the forefront of design.
Optimization of the ept Colibri connectors from 10+ Gb/s to 16+ Gb/s. Graphic: ept GmbH
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