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DRV8301: Possible FET driver heats up

May
Genius 9880 points
Part Number: DRV8301

Hi,

Customer is designing an ESC with the DRV8301 and in the past, they have run into an issue where the FET driver heats up from the FET drive line being mismatched in length. They  suspect it's due to some reflections in the lines due to mismatched lengths. IS this something that should be of concern with the DRV8301? Is there need to tune the length of the drive lines to the FETS?

Thank you.

Regards,
May

  • 0
    TI__Prodigy 620 points

    Hello Maynard,

    I will consult with the team about the mismatched FET drive lines. In the meantime, could you provide the following information:

    • What current are the gates being driven with?
    • Are the recommended bypass and bulk capacitors as close as possible to the DRB8301?
    • What size/length traces are being used for the drive lines?

    The answers to these questions may provide insight as to why the DRV was getting too hot in past designs.

    Thank you!

    Tyler McCulloch

  • 0 in reply to Tyler McCulloch
    TI__Genius 9880 points

    Hi Tyler,

    According to customer, the DRV8301 pads are only supportive of a 10 mil trace, that's the trace width they are using. All bypass and bulk capacitance is as close to the chip as possible, as are the bootstrap caps which are approximately 50 mils from the chip.They pushed the drive current to 30mA. Overall question is to whether or not the trace lengths between the DRV8301 and the gates of the FETs need to be matched for each of the 6 FETs.

    Thank you.

    Regards,
    May

  • +1 in reply to May
    TI__Prodigy 620 points

    Hi Maynard,

    The bypass and bulk capacitance values/location sound great.

    Based on our testing, the difference in trace length at low drive currents does not impact the performance of the driver. A 30 mA drive current should not cause any reflection issues.

    Thanks!

    Tyler McCulloch