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THS3491: THS3491 TINA-TI Simulation problem

MCAV
Prodigy 30 points
Part Number: THS3491
Other Parts Discussed in Thread: TINA-TI,

Tool/software:

I want to use TI's THS3491 current feedback opamp IC in my own circuit. Normally, I work with LTspice, but I couldn't get the spice model of this IC to work stably in LTspice. Therefore, I'm trying to run the simulation in TINA-TI. I downloaded the TINA-TI reference design for the THS3491 (THS3491RGT TINA-TI Reference Design, SBOMAN3.TSC) from TI's website. If I run it as shown in Figure 1, I can get an output. In my own circuit, there will not be a dual supply, I will power it with only +15V. Therefore, when I remove VEE and connect GND instead, I don't get any output. Could you help me with this? Additionally, when I connect the op-amp's pins to GND instead of VMID, assuming that the VMID voltage is already 0V, I also don't get any output. Why is VMID used? I would appreciate your help with this as well.

  • +1
    TI__Genius 11715 points

    Hi,

    VMID is used as a reference to mid supply for the circuit. We use this mid supply to then bias the input signal and gain resistor like shown in the original circuit. This isn't needed and can be removed if it is causing confusion as long as you bias the circuit appropriately. If you set the VEE supply to 0V, it should bias the VMID to 7.5V and will bias the model to the expected mid supply of 7.5V. I would like to add that this model was tuned to work in a gain of 5V/V and with supplies at +/-15V or 30V total. It is hard to say what the model will highlight accurately with a supply of 15V only. We do have performance specs for this device at 15V supply in the datasheet, which is where the most accurate data for this device will be found. You can find data collected at these supplies starting on page 11. 

    Best Regards,

    Ignacio

  • +1
    Guru 48395 points

    THis THS3491 in LTSpice was coming up some years back and I found those files, seem to run ok

    here are the files needed, both .cir and lib, put these all in the same directory, 

    well it is not letting me upload those files, send me an email and I will attach them in an email, msteffes1@comcast.net

  • 0 in reply to Ignacio Vazquez Lam1
    Guru 48395 points

    Well I tried to email those files, permanent error on that email address,