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RE: Static Discharge

Title: RE: Static Discharge

The clamperator networks we use operate just a bit above normal signal voltages.

That means that the voltage is constrained to be within the IC ratings at all times. (Most 10/100 PHY cable inputs and outputs can stand 10 volts or so for short intervals.)

Obviously, this means that by the time you get up near PHY-damaging voltages the clamp has to be stealing ALL of the current. (Things like MOVs do not have nearly sharp enough clamping characteristic curves, Dieter.)

In view of the rise time of the discharge, the amount of energy available in the pulse, and the fact that the clamping network must not upset 100 MHz 100TX lines that are bothered by just a few pF of shunt capacitance under non-clamp conditions, this is a pretty tall order.

Add to that the fact that you do not want to be spending $$ per port for protection.

I have not found any pre-packaged single gizmo that meets all of the requirements.

PHY vendors have been working on this by doing interesting things on the internal pin connections, etc.