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LMG3410R070: Inquiries about FET recommendations for high-speed switching

Grady Lee
Genius 4405 points
Part Number: LMG3410R070


Hi, TI expert

The customer is looking for a FET for high-speed switching.

The specific you want
1) Switching ~ 10MHZ (better than that)
2) Drain Voltage : 150V or more
3) Power consumption: 200W or higher

I don't use it continuously.
It is used about 30 times with 10 times at once every second.

Please check if LMG3410R070 is suitable, and if you have any other parts, please suggest it.

Thank you.

  • 0
    TI__Expert 7455 points

    Hi Grady,

    The 10MHz operation cannot be supported by this device because of the internal gate driver will reach a current limit. 

    Please explain the application and what exactly is meant by "30 times with 10 times every second."

    Thanks,

    John

  • 0 in reply to John Gomez
    Genius 4405 points

    Hi, Jone

    - Application : skincare devices (high-frequency generator)

    - "30 times with 10 times every second." : Set 10 times per second to 1 cycle and use it about 30 times. You can think of GATE ON as 10MHZ.

    If LMG3410R070 is not suitable, is there any other device you can recommend?

    Please check. Thank you.

  • 0 in reply to Grady Lee
    TI__Expert 7455 points

    Hi Grady, 

    After understanding the system requirement, it should be OK. They should put a large VNEG capacitor so that the burst will be supported out of the capacitor, and the buck-boost will recharge it in between bursts. They can probe VNEG when sizing the cap to make sure it isn’t getting discharged much during the bursts.

    Thanks,

    John

  • 0 in reply to John Gomez
    Genius 4405 points

    Hi, John

    Thanks for response.

    But, I didn't understand your answer very well.

    Are you saying that LMG3410R070 is suitable?

    Are there any other devices you can recommend?

  • 0 in reply to Grady Lee
    TI__Expert 7455 points

    Hi Grady,

    Yes, LMG3410R070 is suitable. This device has pin called 'VNEG'. It is the ouptut of the internal inverting buck-boost converter. This inverting buck-boost generates a negative voltage on the VNEG pin. This negative voltage is used to turn-off the GaN FET since it is a depletion-mode FET. The VNEG cap should be sized to be higher than recommended in the datasheet to support the high frequency bursts of the application. 

    Thank,

    John