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LM5118: LM5118 for HB/HS pin low impedance

Rock Shao
Expert 2985 points
Part Number: LM5118

Hi,

At present, it is found that the IC is easy to be damaged during testing and needs help analysis.

IC usually damaged for pins HS and HB, they will have low impedance occurs during the measurement of high-side and low-side MOSFETs (use 5 * 6 MOSFETs and lift them for testing).

How can I prevent this damage?

The test location as the green area

Schematic

Best Regards

Rock Shao

  • 0
    TI__Guru 61695 points

    Hello Rock,

    I am sorry, but please upload a higher resolution schematic. I cannot read the values you are using.

    What do you mean with lifting the MOSFETs for testing?

    Which voltages do you have on VIN and VOUT, what is your load current?

    Please check the voltage on the pins HB and HS when you do not lift anything.

  • 0 in reply to Brigitte
    Expert 2985 points

    Hi Brigitte,

    Let me ask another way. Have you encountered the low impedance of HB and HS in your experience? Is this IC suitable for adding a resistor for the R-C filter to the charge pump capacitor between HB and HS to prevent noise (Blue or red resistor in the picture)? Can it be prevented by add D5?

    Or are there other ways (except that the charge pump is close to the IC) to prevent this damage?

    Thanks 

    Best regards

     

  • 0 in reply to Rock Shao
    TI__Guru 61695 points

    Hello Rock,

    I personally do not know of any issue like this with this part. For solving the issue, the information and measurements that I asked for would be very helpful:

    Which voltages do you have on VIN and VOUT, what is your load current?

    Please check the voltage on the pins HB and HS in normal operation.

  • 0 in reply to Brigitte
    TI__Guru* 76005 points

    Hi Rock,

    Can we assume the issue has been resolved, given no updates for more than a week?  Let me close the thread now but you can re-open it by adding a new post.

    Thanks,

    Youhao