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[FAQ] ESD DC Characteristics

JDJ
Expert 3161 points
Part Number: ESD122
Other Parts Discussed in Thread: ESD401, TVS0500

Hello, 

What is absolute DC input and current thru I/O?

Datasheet shows the spec based on peak pulse but what is the response from static DC voltage? 

I have attached a graph from the datasheet, but still unsure what happens if we inject over 6V DC to IO pin?

 

Thanks! 

  • 0
    TI__Expert 8471 points

    Hello,

    Thank you for using E2E!

    I'll start off by giving you a brief background on these types of protection devices. These diodes are not built to withstand being broken down over a long period of time from a static DC voltage. Their main purpose is to prevent damage from ESD and surge events, which only last for a few nanoseconds and microseconds, respectively. Once the diode is broken down, it generates a significant amount of heat as current goes through it. This will eventually cause thermal failures. Therefore, it is recommended that you only have static DC voltages across the diode that are at or below the rated Vrwm, which in this case, is 3.6 V.

    With that being said, the device may be permanently damaged if stressed beyond the absolute maximum operating free-air temperature of 125°C. Using the junction-to-board thermal resistance and assuming the DMX package, the device will overheat beyond abs max ratings at 36mA at 6V in an ambient temperature environment.

    Please let me know if this answered your question. If it did, please click the "Resolved" button.

    Regards,
    Matt Smith

  • 0 in reply to Matt Smith3
    TI__Expert 3161 points

    I really appreciate the detailed response! 

    We are doing some overvoltage test for safety thru type-C port. We noticed that when supplied 7V, then ESD122 seems damaged which results in abnormal signaling on USB2.0. We think that this ESD diode is ok since it appears to stand a 5V short at least. Do you have a better recommendation which has higher DC rating? 

    From the below link, ESD122 seems to be the recommended device. 

  • 0 in reply to JDJ
    TI__Expert 8471 points

    Hello,

    Is this 7 V applied just to the VBus or is it all data pins? If it's just to the VBus, I would recommend the TVS0500 since those were designed for 5V power lines. If it's the data lines, the next step up in Vrwm would be the ESD401 at 5.5 V Vrwm. However, this part has a higher clamping voltage, so your system would experience a higher voltage during an ESD event. 

    Regards,

    Matt Smith