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Can LT3489 output 1A at 18V with 9-16V input?


Does anyone know about its maximum total power consumption?

Datasheet doesn't indicate that in any detail.

Thanks very much.

Best Regards.

  • Hello Jeronym,

    as rule of thumb you can use following:

    Pout,max <=0,66*Pin, whereas Pin is calculated by Vin,min*ISwitch (just a DC considerations for this formula)

    The 0,66 factor depends on setup, like inductor size, current ripple, frequency, efficiency and so on. A more cautious estimation would use a smaller value down to 0,6

    With your Vin,min of 9V you end up at 22.5W. Multiplyed with 0.65 you achieve a value of 14.85W. But as you ask for 18W Pout(18V@1A), the LT3489 is not capable for this.

    So you have to

    • derate your Pout expectation at lower Vin or
    • increase the minimum input voltage
    • Choose a 'stronger' part with a larger PowerSwitch.

    For latter I would recommend you our LT8364 or LT3581. In addition they do offer more margin in terms of Vin,max.

    You can check the maximum possible power output of your calculated configuration easily with our Power Tools LTSpice or LTPowerCAD.

    kind regards


  • Hi, thank you very much, I am studying how to use the LTSpice!