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LMG3410: LMG3410 inductor winding capacitance and turn-on losses

Part Number: LMG3410

Fig.10 in the LMG3410 datasheet illustrates the set-up used also for turn-on energy measurements.

It would be interesting to know more about the winding capacitance of the 500uH inductor, as to allow a rough estimate of its contribution to the published turn-on energy figures.  

  • Hello, Luca

    Thank you for your question and interest in LMG3410.

    The winding capacitance of inductor is determined by the core dimension, number for turns and layers. The capacitance of the inductor in our test is around 2pF. Please find the link for toroid inductor winding capacitance measurement: g3ynh.info/.../Toroid_selfC.html.
    And you should be able to measure the winding capacitance for your own application.

    Compared to inductor winding capacitance, PCB layout and heat sink will add much more coupling capacitance to switching node and cause additional switching loss. The added coupling capacitance of our LMG3410 half-bridge EVM is around 30-40 pF, and please find more information about the design trade-offs of capacitance coupling to switching node, power loop inductance and thermal performance in the application notes:
    www.ti.com/.../snoa946.pdf

    Please let me know if you have any question.

    Best regards,
    Ted
  • In reply to Ted(Runruo) Chen:

    Very useful answer, thanks.
    Just 2pF stray capacitance for a 500uH power inductor is quite good. I am thus reassured that I can neglect its contribution to the total turn-on losses.
    Best Regards,
    Luca
  • In reply to Luca Ghislanzoni:

    Hi, Luca

    I am glad you find the answer helpful and thank you for your interest of TI GaN product.

    Best regards,

    Ted