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TINA/Spice/TLV9002: Simple -ve feedback amp on KiCAD

Rahul S63
Prodigy 180 points
Part Number: TLV9002
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

I am trying to simulate a simple amplifier using the TLV9002.

Please see the circuit below.

Now, please note the following:

1. TI provides no direct simulation model on PSpice for this specific device. The TINA-Ti simulation works fine. Now from the TINAL simulation, I can extract the PSpice macro and save it to a file and then include it in th KiCAD model above. This approach was used to do the specific simulation. Please see the alternate pin settings below

With these settings however, the model does not converge.

Now two questions:

1. Is it fine to extract the PSpice model this way for devices for which TI does not provide a Spoce model and use them in another simulator?

2. If it is ok, then why does the simulation not converge? What is wrong with my circuit?

THe error messages:

 Reference value :  0.00000e+00
doAnalyses: TRAN:  Timestep too small; time = 0.461199, timestep = 7.5e-14: cause unrecorded.
run simulation(s) aborted

Thanks in advance,

Rahul

  • 0
    TI__Genius 9775 points
    Hi Rahul,

    I'll move this question to the product specific group.

    Herman
  • 0 in reply to Herman Theodorus
    TI__Mastermind 30600 points
    Hi Rahul,

    It looks like your images didn't attach correctly. Could you try again?

    Regarding the SPICE model for the TLV9002, we do provide a .cir and .lib file which is the raw text netlist. Extracting from the TINA macro works as well but you'll save a couple steps if you just download the .cir/.lib

    KiCAD is a simulator that we don't have experience with so I can't comment on what changes to the .cir file will be required to make it work in that simulator. Occasionally syntax changes may be required and it is also possible that there are functions which are supported in PSPICE or TINA that are not supported in other simulators.

    I may be able to give better direction once I see the schematic and error images that you posted originally.

    Best,
    Paul
  • 0 in reply to Paul Goedeke
    Prodigy 180 points
    I am unfortunately unable to upload the pictures. But here is the clr file exported for simulation by KiCAD:

    .title KiCad schematic
    .include "/home/venkata/dev/hardware/cvt_hardware/cvt/spice/opamps/TLV9002.lib"
    V1 /batt GND dc 3.3
    V2 /in GND dc 0 sin(0 1 1 0 0)
    R1 Net-_R1-Pad1_ /out 47K
    C1 GND /batt 1n
    XU1 GND Net-_R1-Pad1_ /batt GND /out TLV9002
    R2 Net-_R1-Pad1_ /in 20K
    .end

    Note that in my model, I had IN+, IN- at pins 3 and 2. V+ and V- at pins 8 and 4 and output of amp1 at pin1. So I had to use a

    Spice_Node_Sequence=3 2 8 4 1

    setting
  • 0 in reply to Rahul S63
    TI__Mastermind 30600 points
    Hi Rahul,

    I don't have much guidance to offer here other than to make sure that the .lib file conforms with the syntax that KiCAD expects. I usually debug convergence issues like this by first confirming that the DC bias point is correct and then trying different starting conditions on the transient sim. In TINA, there are options to start with 0 initial values and similar.

    It also looks like you're using a single supply and that maybe your input signal has no DC component? Test with a dual supply configuration (+/- 2.5V) if you're going to use an input signal that oscillates around 0.

    -Paul