Author Topic: Gigabit ethernet ESD protection  (Read 439 times)

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Offline gaminn

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Gigabit ethernet ESD protection
« on: January 26, 2020, 06:23:44 pm »
Hi,
I would like to createESD protection for my home gigabit switch and gigabit IP cameras (small box with input RJ45 connector, ESD diodes, output RJ45 connector and grounding wire). There is 48V PoE involved (either passive or IEEE 802.3af).

I found some low capacitance esd chips, e.g. http://www.ti.com/lit/ds/symlink/esds314.pdf . These ICs are referenced to ground to protect protected device from surge voltage between twisted pairs. If I understand that correctly, this would mean a problem for PoE - the diodes in ESD chip would short PoE voltage.

How is ESD protection done when PoE is involved? Can I solve the problem by not connecting ESD chip to ground directly but via +- 50V ESD diode?
 

Offline David Hess

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Re: Gigabit ethernet ESD protection
« Reply #1 on: January 28, 2020, 02:32:40 am »
I have one I could take apart but the general solution is to use GDTs (gas discharge tubes) on the exterior interface from each signal to ground and they have a breakdown voltage greater than any PoE standard.
 


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