10GBase-T (10GbE) Ethernet ESD protection

Hi David,

Here is a related thread which is relevant.

ESD protection device for Gigabit Ethernet application

The recommendation is TPD4E1U06. You don't need such low capacitance for 10GbE and increasing capacitance lowers the Rdyn which in turn lowers the voltage presented to the PHY during any ESD event when compatred to lower capacitance/higher Rdyn parts like you have listed.

Regards,

Dear Guy Yater,

the IC that You proposed TPD4E1U06 has following spec regarding Cl and Rdyn :
Cl(f=1MHz, Vbias=2.5V 25°C) = 0.8pF to 1pF
Rdyn (pin to gnd) =1 ohm
Rdyn (gnd to pin) 0.6 ohm

and this is similar to TPD4E05U06 (DQA):
Cl = 0.5pF
Rdyn (pin to gnd and gnd to pin) = 0.8ohm

and the device we are already using in other applications TDP4EUSB30:
Cl = 0.8pF
Rdyn = 0.6ohm ( it don't says is this pin to gnd or gnd to pin in datasheet)

So we would like to use the current IC (TDP4EUSB30) or a IC that goes to 10USON footprint and the device You proposed is in SOT(6) package.

Also we use TPD4EUSB30 to protect 1gb ethernet, usb 3.0 and hdmi(display port).

Thus I have some questions:

1) what is more important regarding the Rdyn the resistance Rdyn pin to gnd OR resistance Rdyn gnd to pin?
2) what You think to use the current device TDP4EUSB30 to protect 10Gbe?
3) is the TPD4E05U06 (DQA) better in specification than TDP4EUSB30 regarding Cl and Rdyn?

4) As You said: 

 You don't need such low capacitance for 10GbE and increasing capacitance lowers the Rdyn which in turn lowers the voltage presented to the PHY during any ESD event when compatred to lower capacitance/higher Rdyn parts like you have listed.

But the part that You suggested has the highest Rdyn=1 ohm, and You said it is better that the Rdyn is lower ?

Best Regards,
David.

Hi David,

Very good questions. Between TPD4E05U06 and TPD4E1U06, the two devices have similar Rdyn  and ESD clamping voltages (I considered the 16-A clamping voltage for TLP, since the ESD clamping voltage for TPD4E1U06 has some ringing in it, making a comparison difficult.) The Rdyn is important, along with Vbr, as they are the biggest contributors to the clamping voltage. The clamping voltage is a good indicator of what voltage the protected IC will see during an ESD event. Typically these are measured under +/-8-kV ESD, and the second peak (at around 30 ns past 1st peak) clamping voltage is where the most energy is present, and a fair equivalent to this is the 16-A TLP clamping voltage, because the second peak in +/-8-kV is caused by 16-A of forced current and ESD and TLP are of similar duration.

For our devices in the 10DQA package I will list the +/-8-kV ESD clamping voltages and the ESD levels that the device can withstand:

• TPD4E02B04:
  • Clamping Voltage: +/-18 V
  • IEC 61000-4-2 ESD:
    • ±12-kV Contact Discharge
    • ±15-kV Air Gap Discharge
• TPD4E05U06:
  • Clamping Voltage: +22/-18 V
  • IEC 61000-4-2 ESD:
    • ±12-kV Contact Discharge
    • ±15-kV Air Gap Discharge
• TPD4EUSB30:
  • Clamping Voltage: +/-15 V
  • IEC 61000-4-2 ESD:
    • ±8-kV Contact Discharge
    • ±8-kV Air Gap Discharge
• TPD4S010:
  • Clamping Voltage: +/-25 V
  • IEC 61000-4-2 ESD:
  • • ±8-kV Contact Discharge
    • ±9-kV Air Gap Discharge

We can see that TPD4EUSB30 has a lower clamping voltage, but it does not meet Level 4 of IEC 61000-4-2, which is +/-8-kV contact and +/-15-kV air-gap. Depending on the targeted ESD protection levels for the system, TPD4EUSB30 may be the best choice.

If Level 4 and 10DQA are needed, I would select TPD4E02B04 for it's lowest clamping voltages in 10DQA. It also has the highest bandwidth of the three, making it more applicable to 1gb ethernet, usb 3.0 and hdmi(display port).

Kind Regards,