Protection of USB 2.0 Applications Series: Different Protection Devices for Different Requirement

Welcome back to our USB 2.0 Applications Series!

If you’ve been following along, you learned that USB-Interface is the most distributed PC interface in the world with a variety of common industry-applications.

Let’s have a look at different protection devices for different requirements and examples of eye pattern tests.

Shown above, there are four different TVS diode arrays and five different ESD suppressor available. To find your products, please explore our product catalog here.

How to Find the Suitable Part?

Answer all these questions and you will find the most suitable part for you.

• Do you have supply voltage to connect for rail-to-rail clamping? Take TVS diode.

• Do you have supply voltage or do you prefer ceramic components? Take TVS diode where VDD pin can float or take WE-VE ESD suppressor.

• Which maximum capacitance can you add to your data lines to pass the eye pattern test? For USB 2.0 line capacitances, up to 5pF shouldn’t cause any trouble.

• What’s the maximum expected ESD voltage that can occur?

• Do you want to protect one or two USB lines? However, connecting one USB data line with two I/Oports of TVS diode lets you get a better performance? Select array type.

We recommend WE-TVS 824 011 for one USB 2.0 port, and 824 015 for two USB 2.0 ports. Designers preferring single line components may choose WE-VE ULC 823 07 050 029 or 823 06 050 029.

Eye Pattern Test

After making a choice of protection element, you have to ensure that your whole interface design meets the requirements of USB specification. Therefore, you can use our protection devices with a small capacitance, which is nearly invisible on the signal lines.

Shown above is an eye pattern test without any protection component placed on two USB 2.0 differential signal lines.

Shown above is an eye pattern test with TVS diode WE-TVS 824 015.

The eye pattern test shows that the WE-TVS do not disturb the USB 2.0 signal. You would get the same result with our other here listed TVS diodes and with the ESD suppressors as well.

The table above shows the cutting edge ultra-low capacitance technology of Wurth Electronics. This new technology enables a channel to channel capacitance, which is almost invisible at normal operating conditions.

Protection of USB 2.0 Applications Blog Series Continues

In case you missed it, read part one of our USB 2.0 Applications Series.

Check back in for more USB application protection tips as we explain how to test protection levels of ESD devices, suggest layout recommendations for single and double USB ports, and more in our concluding post of the series!

To request a quote or to order samples of products to protect your USB ports, click here.

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