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TPS62932: Fixed frequency options

Darren Jenkins
Genius 11656 points
Part Number: TPS62932

Tool/software:

Buck Switching Regulator team,

We have a customer designing with TPS62932, and the switching frequency must be 1 MHz or higher.  The application is extremely cost sensitive.

If the switching frequency is set to 1.0 MHz, there's a 20kOhm resistor pull down on the Rt pin.

If the switching frequency is set to 1.2 MHz, there's no pull down resistor on the Rt pin.  It is tied to ground.

Setting to 1.2 MHz saves the cost of the resistor.  It reduces the efficiency very slightly, based on Webench.  Other than efficiency, can you think of any negative effects of operating at 1.2MHz?

Thanks,

Darren

  • 0
    TI__Mastermind 23156 points

    Hi Darren

    The only disadvantage of 1.2MHz vs 1.0MHz is the reduced efficiency. 

    What's customer's application need? What's the Vin, Vo, Iout and do they have a Tj_rise spec? Under higher fsw customer can select smaller Lout and Cout, this might also be helpful to save cost& solution size.

    Thanks and best regards.

  • 0 in reply to Gui He
    TI__Genius 11656 points

    Thank you.

    The requirements are:

    Vin Max = 24V

    Vin Min = 12V

    Vout = 3.3V

    Output current = 1A at least.  Would like some room so selected a 2A buck.

    Switching freq >= 1MHz

    There's no Tj_rise requirement.  I'm open to any thoughts you have on Tj_rise.

    Do you agree this is a good buck for this application?

    Thanks,
    Darren

  • 0 in reply to Darren Jenkins
    TI__Mastermind 23156 points

    Hi Darren

    I agree we should promote TPS62932 here. connect RT to ground you can save a RT resistor, you can also set fsw as 2.2MHz so that customer can select smaller L and Cout but efficiency will be lower. The webench can help with the design.

    Thanks and best regards.