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LM27402: Minimum on time

Jon Key
Intellectual 920 points
Part Number: LM27402

Hi all,

I have a customer who would like to use LM27402 to generate a 20V to 0.72V Buck Converter switching at 1MHz. I see a MAX duty cycle and minimum off time in the datasheet, but no minimum on time spec. 

Is it possible to use LM27402 in this application?

Thanks,

Jon

  • 0
    TI__Mastermind 23815 points

    Hi,

    You are correct, i would be cautious operating this device at 1MHz. 

    When i tried using webench to ask me generating a design, the operating frequency is around 600kHz. 

    Do you know what is the load current that you are designing into? Maybe we can find another device that might be more suitable

    https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=975E81CFFB5E0DA8

    Thanks

    -Arief

  • 0 in reply to Arief Hernadi
    TI__Intellectual 920 points

    Hi Arief,

    The datasheet says its capable of switching at 1MHz. Do you think this could just be an issue with the webench model?

    What is the minimum on time of this converter?

    If we were to use a different part, it would need to have frequency synchronization and be capable of switching at 1MHz.

    Thanks,

    Jon

  • 0 in reply to Jon Key
    TI__Expert 5900 points

    Jon,

    Its 50ns: minimum on time

    If you have a low duty ration stick with the lowest operating frequency if possible.

    Regards,

    Mathew