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ESD122: Robust connection for ESD protection

Ryo Akashi
Expert 8980 points
Part Number: ESD122
Other Parts Discussed in Thread: TPD3E001, TVS0500

Hello experts,

I have question about ESD protection device connection for USB2.0.
In ESD122 datasheet, it is connected with IO line and GND line in below.
Also, in TPD3E001 datasheet, it is connected with VBUS line and GND line in below.

Could you tell me which connection is more robust?

From datasheet, both of them can be used for USB2.0, but I would appreciate if you would tell me the difference.

Thanks and best regards,
Ryo Akashi
  • 0
    TI__Expert 8471 points

    Hello Ryo,

    The TPD3E001 is an older part where we were still using Vcc pins on our devices. We no longer put Vcc pins in our parts due to possible issues you can read about on page 23 of this guide. It is a 5 V Vrwm part so the protection on the data lines will not be as good since it has a much high clamping voltage. The main advantage you would get from using this part is that you would only need one part for ESD protection. However, if your system can withstand a high clamping voltage, you may want to consider this part. 

    For the highest quality protection, I would use the ESD122 to protect the data lines for USB 2.0 and a 5V surge protection device, such as the TVS0500, to protect the VBUS line. Since the data lines only go up to 3.3 V for USB 2.0, a device like the ESD122 which has a Vrwm of 3.6 V would be perfect. It also has a much lower capacitance. The VBUS is a power line that can go up to 5 V, so a surge protection part like TVS0500 that has a 5 V Vrwm would give you the best protection there. 

    Let me know if this answered your question.

    Regards,

    Matt Smith

  • 0 in reply to Matt Smith3
    TI__Expert 8980 points

    Hello Matt-san,

    Thank you very much for your reply.
    I checked the journal which you introduced, and have some question.

    From journal, the reason why connection with Vcc is to reduce junction capacitance.
    Is junction capacitance same as channel input capacitance(Cio) or line capacitance (CL)?
    I'm little bit confused because the capacitance description is different depends on device.

      

    Also, the possible issue which you mentioned is that other Vcc connected device's damage due to leakage path from I/O to Vcc?
    If so, it's reasonable that IO connection type is more robust than Vcc connection type.

    I would appreciate if you would give me reply.

    Thanks and best regards,
    Ryo Akashi
  • 0 in reply to Ryo Akashi
    TI__Expert 8471 points

    Hello Ryo-san,

    You are correct on all your questions. Junction capacitance is the same as input capacitance and line capacitance. Other device's connected to Vcc could possibly be damaged due to leakage. Therefore, a non-Vcc device is more robust.

    Let me know if you have any more questions.

    Regards,

    Matt Smith