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INA849: Simulation and datasheet bandwidth differ

Nicolas Bouquet
Intellectual 470 points
Part Number: INA849
Other Parts Discussed in Thread: TINA-TI,

Tool/software:

Hello,

I'm interested by the INA849 instrumentation amplifier at a gain of 5~10 but its BW is a little bit too low. I tried a simulation on TINA-TI and LTspice and the simulation results are, for some gains, better than the announced spec. 

Gain expected BW (datasheet) simulated BW (TINA-TI, model 1.0) simulated BW (LT-spice, model 1.1)
x1 (0dB) 28MHz 26MHz 27MHz
x10 (20dB) 13MHz 24MHz 24MHz
x100 (40dB) 8MHz 11.9MHz 11.8MHz
x1000 (60dB) 1.25MHz 1.2MHz 1.23MHz

I'm looking for the -3dB BW.

At gain x10, the simulated BW is almost twice the expected one. If the simulation is good, the INA849 would be the perfect fit for my design.

Simulation parameters : Vs=+/- 15V, REF = 0V, Load = 10k//15pF (copy/paste of the reference design). 

I would like to know if the simulation model is not totally perfect or if my simulation is lacking something.

Many thanks

Regards

  • 0
    TI__Genius 13540 points

    Hi Nicolas, 

    In general, it is to be expected to have slight variation from the datasheet to simulation but the difference you are seeing is larger than would expect. The best way to verify this is to test in the lab on bench. Please give us about a week to validate the gain 10 -3db bandwidth. 

    Regards,
    Ashley

  • 0 in reply to Ashley Kang
    Intellectual 470 points

    ok, let me know about your investigations.

  • 0 in reply to Nicolas Bouquet
    TI__Genius 13540 points

    Hi Nicolas, 

    Wanted to give you an update that I am still working on getting the setup working on bench. I'm first making sure the gain = 1 works before I try to test the gain = 10 and was running into some issues with the hardware. Will aim to update you on my status by the end of the week (12/13). 

    Thank you!
    Regards,
    Ashley

  • +1 in reply to Ashley Kang
    TI__Mastermind 29856 points

    Hey Nicolas,

    Just wanted to close the loop here. This is a known issue with the model, the correct value is the datasheet value. Apologies for any confusion this has caused.

    Best,
    Jerry