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LM61495: LM61495 Webench

F_F_S
Prodigy 140 points
Part Number: LM61495

Hi, I have a problem with your webench power design ...I need to design buck converter with your LM61495 Vin=8-32V Vout=5V Iout=5A ...Tamb=50°C .... some time the webench work and give me the design but often don't work and write me "This design is not stable due phase margin either smaller than 35 or greater than 120."

  • 0
    TI__Mastermind 47060 points

    Hi,
    Can you help narrow down your typical desired input voltage. The reason why there is this issue is because the simulation is trying to pick a single inductor that applies for both 8V min and 32Vmax voltage range. Depending on the inductor and output capacitor selection and the input/output power conditions the stability of the design will be impacted.

    As such I'd suggest narrowing down the input voltage range to something more within the typical expected range. 

    What is your typical application design conditions (VIN,VOUT,IOUT,FSW, and Tamb)? I would suggest choose that and retesting the WEBENCH design.

    Regards,

    Jimmy 

  • 0
    Prodigy 140 points

    Hi,

    I need Vin 8 to 32V , Vout=5V Iout from 1 to 5A max, Tenviroment 60°C , frequency >1Mhz

  • 0 in reply to F_F_S
    TI__Mastermind 47060 points

    Hi,

    I think what was happening was that the design was automatically generating at 400kHz and causing simulation issues.

    Please see this shared export design that I created for a 1MHz design (https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=4932A02CA017B58E). You can tell this is a 1MHz design since the Rt resistor value is 15.4kOhm(see figure 8-6).

    Regards,

    Jimmy