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CSD16325Q5: Mosfet selection for a switching application. Is CSD16325Q5 a proper choice? Or any better are available.

Part Number: CSD16325Q5
Other Parts Discussed in Thread: CSD16321Q5, CSD17556Q5B, CSD16322Q5, CSD16327Q3, CSD, CSD17301Q5A, CSD17303Q5, CSD17308Q3


I am working on development of an application, which requires switching load through a mosfet. The configuration will be as High side switch. The applied voltage will be under 7V and the current drawn will go to more than 7A .but most of the time it will be under 5A. The mosfet needs to be controlled by a 3.3V logic MCU. i would like to directly drive the mosfet from it, without any gate driver, ie,  GPIO driving the gate. The operating frequency will be 1kHz, but this is yet to be decided. But 10kHz will be the ceiling. Other requirements are low Rdson, low switching losses (should not get heated up).

I am looking at CSD 16325Q5 for it, though i have other options like CSD16321Q5, CSD17303Q5 and CSD17301Q5A. I have samples for these. Other options, which appear useful are CSD16322Q5, CSD17556Q5B and CSD16327Q3. 

Are the above mentioned FETs suitable for my application? Or any other ones would work better?


  • Siddhesh,
    Thanks for posting
    All the of devices you indicated would be ok to use except the CSD17556Q5B ( as this is not rated for resistance @ 3V).

    A small SON3x3 lower cost alternative I would to recommend is the CSD17308Q3, even with 7A this would still only dissipate <1W and would expect to work find in your application.

    This is a lower charge device compared to the other parts you selected also. This should make it simpler to drive straight from a GPIO but the speed at which a FET turns on is determined as much by the gate drive strength as the MOSFET itself. My concern is your GPIO may not have enough strength to turn the device on as quickly as you may require in your application.

    As quick check could be done to estimate the switching time using the charge of the device and current of the gate drive, Q=t*I, so for a rough estimate of the FET switching time you could divide the total Qg of the FET @ 3.3V (in the case of the CSD17308Q3 ~2.8nC typ, add say ~30% to get to a max expected Qg of 3.7nC). Then you can divide 3.7nC by the gate drive current and you can get a rough approximation for the time it takes the device to reach 3.3V.