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LMR43620-Q1: PSpice model for 5V output

Youhei Miyaoka
Expert 3865 points
Part Number: LMR43620-Q1

Tool/software:

Hi team,

My customer want to do 5V output simulation. But seeing from product page, there is only 3.3V output simulation model. 

Can you provide 5V model or teach me how to do if there is not 5V model.

Regards,

Youhei MIYAOKA

  • 0
    TI__Guru 72035 points

    Hello

    Let me speak with the application engineer and I will get back to you as soon as possible.

    Thanks

  • 0 in reply to Frank De Stasi
    TI__Guru 72035 points

    Hello

    Sorry for the delay.  Our team is looking into this.

    Thanks

  • 0 in reply to Frank De Stasi
    TI__Mastermind 24115 points

    Hi Youhei,

    I was able to get the PSPICE model to output 5 V. You just need to put an appropriate resistor ladder on the FB pin in the model. You may also need to change the inductor to a more appropriately sized one according to equation 7 in the datasheet. You will also want to change your output load resistor (the model has it as 3.3/2 but you will need to change it to 5/2 for 5 VOUT, 2 A operation).

    You can also use webench to quickly estimate parameters such as efficiency and bode plot stability if you are having trouble with PSPICE. Select the adjustable or fixed 5 V version of this model to simulate a 5 V output. I have created a design for you as a starting point for your convenience: WEBENCH LMR43620-Q1 5 VOUT.

    A caveat is that these simulation tools are provided to help but are only estimations on performance. TI recommends conducting further bench validation on your end to ensure the device is operating as expected with your application's parameters before moving forward with the design.

    Thank you,

    Joshua Austria

  • 0 in reply to Joshua Austria
    TI__Expert 3865 points

    Hi Joshua,

    Understand. However my customer couldn't output 5V, could you review their condition below?

    Regards,

    Youhei

  • 0 in reply to Youhei Miyaoka
    TI__Mastermind 24115 points

    Hi Youhei,

    I understand the issue. It seems that the PSPICE model is built with a 3.3 V reference voltage. You can achieve 5 VOUT using an adjusted resistor ladder that is different from the datasheet

    Please keep in mind that this design for you resistor ladder will not be applicable to the bench as the device has a 1 V reference voltage, but this should be ok for the soft start/transient analysis. Should you need further analysis, you can use webench to simulate 5VOUT. Here is the design I have started for 5 VOUT operation with the fixed version of this device: https://webench.ti.com/appinfo/webench/scripts/SDP.cgi?ID=BDC46A19713B04AE

    Thank you,

    Joshua Austria