This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65982: MOSFET selection for TPS6598x PPEXT

Part Number: TPS65982

Hi all,

 My customer want to be 20V4.25A power source by using TPS65982 so they need to choose MOSFET for external power path's control. Is there any spec. (Rdson, Qg, Ear,...) for my customer's referrence to choose a suitable MOSFET in 98x's PPEXT path? Thanks for your response.

Best regards,

Gary Teng.

  • Hi Gary,

    There's no specific specification for all the parameters you've listed.

    You can use any good FET which can support 15A of higher and it should be fine. The reason I am suggesting a 15A FET is because upon connection there will be hign inrush current which will be much higher than 4.25A and the FET should survive this inrush current.

    Alternatively you can refer the reference design and use the part used in the reference design.

    Thanks,
    Rahul
  • Hi Rahul,

    My customer use APM4826 in their design, but this MOSFET can't pass short test from Vbus side and it will be turned out. In the same condition, SG30N04S and TI's CSD17309 can pass the test. Customer want to know how to choose suitable MOSFET.

    APM4826:    <<< do you think its Id is not large enough?

    Gary

  • Hi Gary,

    I looked at the datasheet of APM4826 and the reason it's not surviving the short test is because of it's low current rating.

    This FET has a lower current rating as well as lower power dissipation rating. Both of which leads to FET damage when there's a high power dissipation across the FET in short circuit condition.

    TI's CSD17309 has high current rating and power dissipation figures which helps it during the short circuit and it survives till the protection mechanisms kicks in.

    I assume it's the same case with the SG30N04S, but can't confirm as I couldn't find the datasheet of it.

    Thanks,

    Rahul