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TINA/Spice/THS4541: A TINA-TI simulation circuit for phase compensation verification

Part Number: THS4541

Tool/software: TINA-TI or Spice Models

Hi support team,

Our customer is considering THS4541 as a preamplifier of ADC input.

They are just starting simulation with TINA-TI.

Is there a simulation circuit for verifying the phase compensation of a fully differential amplifier like the THS4541?

Best regards,

Tomoaki Yoshida

 

  • Hi Tomoaki,

    I am not quite sure what you mean by "simulation circuit for verifying the phase compensation".

    Are you referring to Open Loop Frequency Response that can be used to measure phase margin perhaps? or are you referring to closed loop configuration such as shown in this THS451 TINA-TI reference: http://www.ti.com/lit/tsc/sbom907 ?

    Let us know

    Herman

  • In reply to Herman Theodorus - WEBENCH Design Center:

    Hi Herman-san,

    Thank you for your reply.

    I am glad to either reference circuit, but I want a reference simulation circuit especially for open loop frequency response characteristics.

    I am unfamiliar with TINA-TI, so it is very helpful to have a simulation environment as it is.

    Best regards,

    Tomoaki Yoshida

     

  • In reply to Tomoaki Yoshida:

    Thank you for the clarification.

    Attached is the open loop test bench that you can use.

    Regards,

    Herman

    THS4541 Open Loop.tsc

  • In reply to Herman Theodorus - WEBENCH Design Center:

    Hi Herman-san,

    Thank you for your support.

    It was very helpful for me.

    Best regards,

    Tomoaki Yoshida

     

  • In reply to Tomoaki Yoshida:

    Hi Herman-san,

    I have a question for open loop test bench.
    I often see a open loop simulation that cut the feedback loop with the Hi-z element.
    Since the bias conditions of the actual circuit are different on the test bench that I got, I would like to analyze the open loop with the circuit assembled.

    I think that I can do it by modifying the closed loop test bench, but what should I do?
    I am in trouble because I do not know how to input AC to virtual ground point.

    please support me.

    Best regards,
    Tomoaki Yoshida

     

  • In reply to Tomoaki Yoshida:

    Hi,

    I want to simulate to set the peripheral circuit constants of THS 4541.
    In order to set the compensation capacity, I would like to verify the AC characteristics of the open loop with an actual circuit load.
    Should I adjust C1 and R2 in the circuit THS4541 Open Loop.tsc I taught above?
    I assume that the feedback resistance from the output of the amplifier to the input is 2.5kΩ and input resistance is 1kΩ.
    In this case, how much resistance should be set R2?

    I am sorry if it's a bad question.

    Best regards,
    Tomoaki

     

  • In reply to Tomoaki Yoshida:

    Tomoaki-San,

    I am so very sorry for missing this post. I just found it as I was cleaning my old posts that I missed your reply on this one. My apology.

    To answer your question, your C1 and R2 should be set to the typical loading you have. To figure out the actual R2, you should use R2new = R2 || (R1 + R3) to include the impact of the feedback resistors.

    Let me know if you still have more questions.
    Regards,
    Herman

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