I have never protected my USB interfaces for microcontrollers until a USB port of my PC stopped working because of a bad connection aparently. So I'm starting to protect them but I found some ESD IC's that protect them but my question is...

Is there a simple way to do it with discrete components?

I came across with some schematics using a pair of resistors and a pair of zener diodes.

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Is that enought to protect them?

Extra info on usb protection: http://www.digikey.com/techxchange/message/6040


NXP has a good document on USB ESD protection.

The paper shows bidirectional TVSs on D+ and D-, as well as a unidirectional device on VBUS. No resistors required.

TVSs are designed to withstand ESD surges without the need for limiting resistors, plus they react quickly. Regular Zeners aren't as robust.

  • \$\begingroup\$ Yes, I saw that too (posted the link in my previous edit). Actually I just bought ESDA6V1W5 from ST mouser.com/ds/2/389/CD00064033-97237.pdf But it also could be nice to see it implementing discrete components. Aparently a lot of people its interested in this subject. \$\endgroup\$ – Sein Oxygen Apr 4 '13 at 2:23
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    \$\begingroup\$ You can do it with discrete TVSs, it can be a bit cumbersome from a PCB layout standpoint. I've had good experiences with those ESDA transil devices protecting I2C and digital output lines in the power supplies I've worked on. \$\endgroup\$ – Adam Lawrence Apr 4 '13 at 2:37

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