This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

  • Resolved

TINA/Spice/TINA-TI: The question between FilterPro and TINA-TI

Part Number: TINA-TI

Tool/software: TINA-TI or Spice Models

Hi,

I try to rebuild FilterPro filter in TINA-TI.

Case 1. Lowpass, Multiple Feedback, Butterworth, order 2, Gain: 1V/V, Frequency:10Hz

The input signal and output signal inversed.(-1V/V)

The frequency response is different too.

DPG3.TSC

Case 2. Lowpass, Shallen Key, Butterworth, order 2, Gain: 1V/V, Frequency:10Hz

The frequency response looks like different.

DPG2.TSC

I don't know where the problem is.

I would appreciate any help.

YHH

  • YHH,

    When I look at your picture above, I notice that they are actually the same. All of them shows f-3dB of 10Hz whether it's FilterPro or TINA simulation.

    Are you referring to the higher frequency discrepancies perhaps such as around 1MHz for your first case and 10kHz for the second case? If this is what you meant, it has something to with with the opamp. In FilterPro, it uses ideal opamp while in TINA, you're using real opamp model.

    If you want to duplicate FilterPro plot, you can replace the opamp in TINA with ideal opamp by using VCVS (Voltage Controlled Voltage Source) component and set the gain to let's say 10000x

    Herman

  • In reply to Herman Theodorus:

    Hi Herman,

    Thank you for your reply.

    When I use VCVS, it looks like almost the same with FilterPro. (besides the phase)

    But I don't know why input/output signal are Inverting. (Gain is 1V/V in FilterPro)

  • In reply to Yu-Hung:

    It is inverting because you choose an inverting configuration. Multiple Feedback LPF architecture is an inverting configuration. If you want it to be non-inverting, then you choose the other one which is Sallen-Key architecture.
  • In reply to Herman Theodorus:

    Hi Herman,

    Yes, I know.
    But I guess the Gain is -1 V/V, not 1 V/V.

    right?
  • In reply to Yu-Hung:

    Yup, that's correct.

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.