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CSD17302Q5A: Question about

Albert Sun
Intellectual 350 points
Part Number: CSD17302Q5A

Hi Team,

Why is the junction capacitance of MOSFETs usually tested at f=1MHz, and how does the frequency affect the junction capacitance? The image below is taken from the D/S of csd17302q5a.

-A

  • +1
    TI__Mastermind 34750 points

    Hello Albert,

    Thanks for your interest in TI FETs. To the best of my knowledge, 1MHz is the standard frequency where TI and most power MOSFET vendors specify capacitance in their datasheets. In general, I think 1MHz was chosen because FETs typically switch at <= 1MHz in switch mode power applications. I was able to find characterization data for some other TI N-channel FETs and Ciss and Coss are pretty flat over frequency although Coss shows a 30% - 40% increase above 10MHz. I think that may be due to the package parasitics. I have not been able to find any Crss vs. frequency data but I would assume that is fairly flat as well. Also, the internal gate resistance, RG, typically decreases with increasing frequency. Hope this helps. Let me know if I can be of further assistance.

    Best Regards,

    John Wallace

    TI FET Applications