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TINA/Spice/INA333: TINA Simulationm Anomalies

Bryan Hsieh
Prodigy 120 points
Part Number: INA333
Other Parts Discussed in Thread: TINA-TI, OPA330,

Tool/software: TINA-TI or Spice Models

Hi Everyone,

I have been trying to get used to using TINA, which is a great simulation software when it does work, but I just seem can't get it to work.

For example the schematic shown below, when I add in the instrumentation amplifier circuit, OPA330 for some reason stops working.

If I remove INA333, then it works again. I have encountered the same issue in the past, it seems to me that TINA has problem simulation more than one IC?

Simulation with both INA333 and OPA330, as shown by the graph, Vout which is the output from OPA330 is at 1.65 flat, when I should see a sine

wave with 200mVpp biased at 1.65V.

VG2 = sine at 100Hz with 200mVpp and biased at 1.65.

Simulation without INA333 circuit, as shown in the graph, once INA333 has been removed, OPA330 simulates correctly.

VG2 = sine at 100Hz with 200mVpp and biased at 1.65.

I have not changed the OPA330 circuity at all, I only removed the INA333 circuity.

Is there a reason why this is happening?

The reason for the OPA330 circuit is because I was using it to remove the DC offset from the INA333, however it wasn't wokring and after some debugging I found

that the opamp just wasn't doing anything.  Please see this post https://e2e.ti.com/support/amplifiers/precision_amplifiers/f/14/t/633065.

Thanks for the help.

Rgs,

Bryan

TINA_SIMULATION.TSC

I have included the schematic from TINA here.

  • 0
    TI__Mastermind 33250 points
    Bryan,
    Thanks for the inquiry.
    I will take a look at your circuit and let you know what I find by tomorrow.
    Regards,
    John
  • 0 in reply to John Miller - Sensing
    TI__Mastermind 33250 points

    Bryan,

    I was able to reproduce your results. 
    The thing that kept bugging me were the persistent connection warnings associated with wire connections made with named wires rather than jumpers (e.g VCC and VREF).

    The thing that got the circuit working was to replace the named wires with un-named wires and making the VCC and VREF connections with jumpers.
    Jumpers are the symbol on the Basic tab that look like a 'T' laying on its side.
    The weird thing was that simply removing the wire names and leaving the original wire wasn't enough. They had to be replaced with new, un-named wires.

    Once that was done, the circuit seemed to work.
    The rev'd circuit is attached.

    Please let me know if you have any more questions.

    Regards,
    John

    TINA_SIMULATION_rev.TSC

  • 0 in reply to John Miller - Sensing
    Prodigy 120 points
    Hi John,
    Thank you so much for your help, you have saved me countless hours of head scratching.
    I guess to avoid a similar problem in the future I should always use jumpers instead of named wires.
  • 0 in reply to Bryan Hsieh
    TI__Mastermind 33250 points
    Bryan,
    Using jumpers instead of naming wires is the best way to make a connection.
    As a reality-check I looked in the TINA Help and it doesn't really say anything about making connections, only wire/bus naming conventions and limitations. My guess is that it is intended for convenience of identifying outputs.
    Regards,
    John