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Meeting New USB ESD Challenges with TrEOS Protection
It is crucial for designers of electronic systems to protect every product against the destructive forces of ESD. Systems, components and interfaces are all at risk, especially as chip geometries continue to shrink and data speeds get faster. Innovative products often bring with them new demands and fresh challenges requiring new solutions. One such case is the latest USB interface standard, which brings faster data rates and the new USB Type-C connector.
New level of protection
For USB 3.1 a new level of ESD protection is necessary, mostly because of its very high 10 Gbit/s data rate. Table 1 provides a summary of recent USB standards and their maximum data rates. At double that of USB 3.0, the fast data rate makes it more difficult to maintain signal integrity. For example, the small inherent capacitance of ESD protection diodes becomes a contributing factor in potential signal disturbances. Also, the smaller structures of fast systems tend to be more sensitive to ESD, demanding a more robust ESD solution.
Table 1: Summary of USB maximum data rates
With our new TrEOS Protection device family we have achieved a higher level of ESD protection, ideal for the USB 3.1 interface. It offers an industry-benchmark combination of low capacitance, high system-level robustness and low clamping voltage.
Meeting signal integrity requirements
Capacitances of TrEOS devices are in the 0.3 pF range for uni-directional devices, while bidirectional devices offer capacitances down to only 0.1 pF. Low capacitances alone are not sufficient to achieve a system with good signal integrity. Signal lines should be as short and symmetrical as possible, and stubs avoided. NXP offers package concepts, which support RF-friendly routing.
This post offers just a taste of what you can find in our new technical white paper ‘ESD protection for USB 3.1 and Type-C’: It gives you an in-depth analysis, considering how the changes to this popular interface relate to the challenges of protecting USB 3.1 products from ESD strikes. It covers topics including how to read eye diagrams and transmission line pulse (TLP) measurements, system level protection and much more. It also includes a look at some new solutions – including the TrEOS Protection device family. You can download the white paper on our ESD technology site.
