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ESDS314: Surge/ESD Protection for USB Vbus

Allan Fan
Expert 6500 points
Part Number: ESDS314
Other Parts Discussed in Thread: STRIKE, TPD1E10B06, ESD321

Hi expert,

Customer is looking for USB2.0 protection solution for both Vbus and data line at least 20A(8/20us Ipp). 

We are considering ESDS314. Would you please help clarify the question below and/or advise recommended solution? 

1. the typical value of TLP clamping voltage in the specification is 5.5V, and the TLP curve exhibits a snap-back phenomenon. May I learn from your experience is the ESDS314 protector is recommended for use in the USB2.0 power line? Is there a risk of latch-up? We are worry if the snapback might burn out the protector or we should choose other type of protector.

Regards,

Allan

  • 0
    TI__Genius 14960 points

    Hi Allan,

    There's no risk of latch up here, since this device only has shallow snapback the holding voltage (Vh) won't fall below the working voltage.

    Deep snapback diodes where the holding voltage is within the working voltage range (Vrwm) do risk latch up after an ESD strike. The deeper the snap back or the lower the holding voltage, the more likely latch-up will occur. 

    Regards,

    Sebastian 

  • 0 in reply to Sebastian Muriel
    Prodigy 10 points

    According to the Application Note: ESD and Surge Protection for USB Interfaces, in Chapter 1 of USB 2.0, it is recommended to use different ESD protectors for the Power line and Data line of USB circuits.

    I have reviewed two different ESD protector characteristics, and the TLP curves show significant differences. It is suggested to use the non-snapback TPD1E10B06 for the Power line and the snapback ESD321 for the Data line.

    May I ask what the difference is? Is it because snapback products are not recommended for use on Power lines to avoid the risk of latch-up?

  • 0 in reply to Alan Hsu
    TI__Genius 14960 points

    Hi Allan,

    The main concern with latch up is with deep snapback diodes, where the holding voltage would be within the working voltage range.

    Let's say a deep snapback diode was placed on a power line and it clamps an ESD strike. If the diode is still conducting and the power line begins operating normally it would supply large amounts of current (A range) that would likely be higher than the hold current of the ESD diode (mA range). 

    There is typically more over/undershoot on power lines than data lines due to parasitics, as well as alot more current flowing through the power line. This makes the risk of latch up greater than on a data line.

    Data lines typically only have mA of current flow so there is less risk of the signals current being higher than the hold current of the ESD diode.

    Our portfolio doesn't currently offer deep snapback devices, only shallow snapback where the holding voltage is still above the working voltage so latch up shouldn't be a concern on the data line with ESD321.

    Regards,

    Sebastian