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Webench simulation of LM26001

Other Parts Discussed in Thread: LM26001, LM26003

I would like to confirm LM26001 simulatuon by webench.

I cannot simulate in the below conditon;

- Vin: 16V < Vin < 38V

- Vout: 12V

- Iout: 1A

I tried it but I saw the comment;

- This design is not stable due phase margin......

- Circuit Calculator can't create design.

In the case of LM26003 and Iout = 2.5A, I could simulate it.

Why can I simulate it?

Best regards,

Atsushi Yamauchi

 

 

  • Hello,

    Thank you for your interest in Texas Instruments' power management solutions.  I apologize for any issues you may have run into while using WEBENCH® for your LM26001 design.  

    I am able to create a design using the conditions you have provided, and I do receive the same comment regarding the phase margin being low.  I need to investigate this issue some more, since there seems to be a mismatch between the WEBENCH calculated Phase Margin and the Simulation Phase Margin.  

    I will get back to you as soon as I am able to identify a solution.

    If you have any other questions or concerns, please let me know.

    Regards
    Jonathan Arzadon
    Applications Engineer
    WEBENCH Design Center
    Texas Instruments

  • Hello,

    Sorry for the delay in my response.

    I have looked into the issue, and found that the phase margin is indeed low (~12deg) for your input requirements.  However, the design does create in WEBENCH and does indeed work on the bench with a low phase margin, since I was able to build the design on a board and test it in the lab.  

    If you still would like to use LM26001 for your design, I can share with you an updated design in WEBENCH with a higher phase margin and better stability.

    In the case of LM26003 with Iout = 2.5A, the reason why you were able to create the design in WEBENCH, and did not receive a warming message, was because the compensation components that were used for this design were different from the LM26001 design, which provided better stability for the circuit.

    Please let me know if you have any other questions or concerns, or if you would would still like to use the LM26001 with an updated Bill of Materials and better stability.

    Regards,
    Jonathan Arzadon
    Applications Engineer
    WEBENCH® Design Center
    Texas Instruments