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LM25149-Q1: MOSFET Vth selection

Yuta Kurimoto
Expert 8260 points
Part Number: LM25149-Q1

Hello Team,

In the LM25149-Q1 datasheet, the VBOOT-SW-UV-F is 2.59V(typ).

Does it mean that we should choose MOSFET which Vth is lower than 2.59V?

Thanks,

Yuta Kurimoto

  • +1
    TI__Mastermind 22299 points

    Hi Yuta,

    Yes use a MOSFET with Vth lower than 2.59V.

    If the BOOT-SW is discharged to ~2.6V and the controller tries to turn on the MOSFET the RDSON will be larger.

    Larger RDSON will increases MOSFET losses. This is increase losses only for a moment until BOOT-SW recharges but can have worse light-load efficiency and dropout performance.

    You will get the best performance with Vth < 2.59V.

    Hope this helps,

    -Orlando