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LM98640: LM98640 ESD pulse

Matth. B.
Expert 1135 points

Part Number: LM98640

Hi,

I'm using the LM98640 component in a new design.

The input of LM98640 is connected to another component through a 100nF capacitor.

In my design, there is a risk of overvoltage before the capacitor. This pulse can pass the capacitor and a peak voltage of 15V peak current of 800mA could appears on the input pin OS-. Maximum energy provided by this pulse is 7.2µJ.

By simulation of the HBM ESD test, it seems that the input of LM98640 is capable to handle more than 11µJ.I simulate the input pins by a resistor of 16 Ohms connected to a DC voltage (VCLP).

Could you confirm me that such this pulse (15V peak / 800mA peak / 7.2µJ) canno't dammage the LM98640.

Thanks

  • 0
    TI__Mastermind 49176 points
    Hi Matthieu,

    We have received your inquiry about the device LM98640. Let me check with the team and will get back to you by next week.
  • 0 in reply to Praveen Aroul
    Expert 1135 points
    Hi Praveen,

    I come back to know if you have any feedback about my request?

    Thanks
    Matthieu Baque
  • 0 in reply to Matth. B.
    TI__Mastermind 49176 points
    Hi Matthieu,

    I apologize for the delay in my response.
    I am moving your post to the Imaging AFE forum where the device is currently being supported.
  • 0
    TI__Genius 14485 points

    Hello Matthieu,

    I have asked my product engineer to find the ESD data for this device so we can compare it to your stated conditions. I will update you when I have the data.

  • 0 in reply to James Lockridge19
    TI__Genius 17035 points

    Hello Matthieu,

    It is difficult to apply ESD test results to other overstress scenarios.   It  really depends upon the duration fo the pulse.   An ESD pulse is only nanoseconds.

  • 0 in reply to Kirby Kruckmeyer96848
    Expert 1135 points

    Hi Kirby,


    I agree that it's difficult to use ESD test results for other tests but I would like to have an opinion.

    Could you explain me what could be the problem, is a thermal issue on the ESD diode due to pulse duration? Because my current and voltage are under the current and voltage for ESD test.

    About the duration of the pulse, I have 300ns or 400ns for HBM test in my simulation.

    For my own overstress pulse, duration is more like 2us.

    Thanks

    Matthieu Baque

  • 0 in reply to Matth. B.
    TI__Genius 17035 points

    I would expect your conditions to damage the part.

    It is a thermal condition due to the long pulse time.

  • 0 in reply to Matth. B.
    TI__Genius 14485 points

    Matthieu,

    My product engineer responded to me with the ESD information. The HBM ESD voltage the LM98640 can withstand is 4000 V. For this test, we supply 4000 V with a peak current of 2.40-2.93 A for 2-10 ns. The decay time of the peak is 130-170 ns.

    The ESD test is only to fulfill the JEDEC standard for ESD events on our device. I understand that from a physical standpoint, your transients may be similar to ESD events. It is possible that the device will survive as you have calculated. However, TI cannot officially guarantee or recommend that this device be used in this way because we have not explicitly tested it for the type of transient conditions you say it will experience.

    That said, if you believe it will work based on your calculations, my recommendation is to test multiple units under the transient conditions to get an idea on the survival rate/reliability for the device. However, if you do experience reliability issues here, TI is not liable because we do not guarantee this specific situation in the datasheet.