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TPD4E02B04: ESD protection for PCI Express

Yuichiro Mori
Prodigy 10 points
Part Number: TPD4E02B04

I am considering that it is connected TPD4E02B04 to PCI Express Gen. 3 lanes as ESD protection. In the case of PCI Express, it is necessary to insert an AC coupling capacitor to the TX lane.
Therefore, I have to select the placement of TPD4E02B04 is PCI Express connector side or the opposite side with respect to the AC coupling capacitor.
Would you tell me about it?

  • 0
    TI__Expert 8471 points

    Hi Yuichiro,

    The general rule of thumb for ESD diodes is that you should try to place them as close to the connector (ie the ESD source) as possible. This will give you the most optimal protection from ESD transients. However, in certain applications with other protocols, there is sometimes a significant DC bias on the connector side used to power other circuitry. If this DC bias exceeds to Vrwm of the diode (in this case 3.6 V), a diode with a higher Vrwm should be selected. Unfortunately I'm not extremely familiar with PCI Express, so I don't know if any significant DC bias/common mode voltage over 3.6 V would be present. Do you know this information? 

    Regards,

    Matt Smith 

  • 0 in reply to Matt Smith3
    Prodigy 10 points

    Hi Matt

    Thank you for your reply.
    PCI Express data lanes don't have any DC bias because of AC coupled from TX side. Also, those TX swing voltage are 1.2Vpp (max.) .
    According to your advice, I will try placing this diode on the connector side.

    Thank you.