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WEBENCH® Tools/LM3488: lm3488

mario soccini
Intellectual 730 points
Part Number: LM3488

Tool/software: WEBENCH® Design Tools

Hi.

I use LM3488QMMX/NOPB.

I would like to know if the on/off control in my schematic is ok.

I used webench about design…

Thanks.

Mario.POWER SUPPLY 100V.pdf

  • 0
    TI__Guru* 78400 points
    Hi Mario,

    Thank you for considering the LM3488. There must be a resistor inserted between the FA/SYNC/SD pin and the external pull down FET drain, to set the switching frequency. When the FET is off, the FA/SYNC/SD pin is pulled high by the 5V through two resistors (one is your R28, the other is the newly inserted one), to shut down the circuit. When the FET is on, the drain pulls to GND and the FA/SYNC/SD pin sees the inserted resistor to GND, setting the operating frequency.

    Hope this clarifies.

    Thanks,
    Youhao Xi, Applications Engineering