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TINA/Spice/INA116: Noise Modeling in TINA

Derek Belle
Intellectual 505 points
Part Number: INA116
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Hi,

As talked about before there is no TINA model for the INA116. Previous suggestions have been to use the OPA129 in a 3 opamp instrumentation amplifier setup. 

Do you guys have any suggestions on modeling the noise of the INA116? Would using the OPA129 still be valid?

Thanks

Derek

  • 0
    TI__Expert 6250 points
    Hi Derek,
    I believe that using the OPA129 approach should still work here, but I'll double check on that Monday for you.
  • 0 in reply to Alexander Davis
    TI__Guru 60610 points

    Derek,

    OPA129 model is an old macro-model that simulates only a broadband noise.  But as long as you do not limits the bandwidth to a very low frequency by adding a low pass filter at the INA output, or by placing the INA116 in gain greater than 100, using OPA129 macro-model to implement tree op amp INA116 should give you relatively decent estimate of the expected noise.  Having said that, OPA129 macro-model underestimates the broadband noise at 13nV/rt-Hz instead of 15nV/rt-Hz so if you want to be more precise you need to multiple the simulated noise by the correction factor 15/13*sq-rt(2) =~1.63 - sq-rt(2) comes from two uncorrelated noise sources of two first stage op amps adding together).