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Question about LTM4653 simulation using Loop Compensation Design


My customer will use LTM4653 and LTM4630A and before applying these devices, they want to confirm simulation results from LTSPICE.

But they say that the simulation time of their design  takes  long time,  so they want to use  a Loop Compensation Design (DCDC modeling) for reducing simulation time.


【LT - Loop Compensation Basics Buck Converter CCM】

In case of LTM4630A, when they use this modeling design, they got a similar results with stability value of Loop Comp. tap in LTPower Cad.

But in case of LTM4653, they have some problems to do the modelling desing and they can;t get right vlues.

Q) Would you confirm attached modeling file of LTM4653 and let me know your opinions?

     For your reference, I also attached LTM4630A  modelling files.

  Please advise me.



  • Except for phase at 100Hz, the results are very close, and 100Hz phase is not a concern.

  • The phase variance at high frequency is likely because the LTspice model is linear and does not account for the effects of approaching the switching frequency. 

  • Dear dkb,

    Thank you for your reply.

    But I have some questions about your answers.

    Actually my customer's request get similar values both a result value of bode plot and stability value of Loop comp tap in LTPower Cad. 

    This is for using DCDC modeling file instead of LTSpice simulation at testing with various environments,

    So they request your opinions about DCDC modeling files and LTPowerCAD files.

     And  also they say that  DCDC modeling of LTM4653 is hard to implement because LTM4653 has different architecture from general DCDC like LTM4630. 

    So they want to get your advices about a DCDC modeling methods of LTM4653.


          Q1) Would you let me know your opinions about a DCDC modeling file of LTM4630 that I attached?


          Q2) Would you let me know your opinions about a DCDC modeling file of LTM4653 that I attached?

          Q3) Would you explain how to implement a DCDC modeling file of LTM4653 in detail? 


          Q4) About your answers, is your answers about DCDC modeling file of LTM4653?

               They want to get similar values  between DCDC modeling file and LTPowerCAD file.

               The standard is a LTPowerCAD and they want to meet values of DCDC modeling file to LTPowerCAD file.