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Original question:

LM108AJ-8 replacement

Equivalent models to LM10, LT1101, LM1558 for simulation

Scott Miller1
Intellectual 515 points
Other Parts Discussed in Thread: LM1558, LM10, INA827, LM358, LMC7111, LM741, LPV321-N, LPV321, OPA364

I want to create a simulation in TINA with LM10, LT1101, LM1558 in the design (existing design in a current product).  However, none of these are in TINA or SPICE for simulation. Can anyone suggest equivalent models? 

If LT1101 is an IN Amp, so if nobody can suggest a similar model, I am going to use INA827 (will set a gain of 10 with 16k resistor, as the LT1101 is configured as gain=10). LM1558 looks to be just a run-of-the-mill OpAmp, so I will use LM 258. 

LM10 is a little more tricky... it has the built-in reference op amp (which is the portion that my current product design uses.  Ideas??

  • 0
    TI__Mastermind 39210 points

    Hi Scott,

    We will check with the product team and get back to you.

  • 0 in reply to Nikhil Gupta (Product Folder Models)
    TI__Mastermind 30600 points

    Hi Scott,

    I think you'd be safe simulating the LM1558 with the LM358 model. Fair warning, this model is pretty old and may not be good for much more than getting you started or a rough guess. I can't really comment on the comparison of the INA827 and LT1101, but I think your strategy of choosing a similar instrumentation amp is a good one.

    As far at the LM10, this is tough one. My first thought would be to choose an op amp with similar specs and set up a simulation with two identical amps, one as the reference and one as the main amp. One good option would be the LMC7111, which shares a similar GBW, SR and other specs.

    What type of simulation are you looking to perform? If you need a stability simulation then that might be tough because output impedance and Aol are going to matter the most and you're using substitute devices which may not match well. If you're looking for more of a DC type simulation, you may be able to look at the SPICE files and change some of those parameters yourself to get them to match.

    If you post your schematic for the relevant portion of the circuit, it might help us come up with some more ideas on how best to model and get a sense of what you're trying to accomplish.

    Thanks,
    Paul

  • 0 in reply to Paul Goedeke
    TI__Mastermind 30600 points
    Hi Scott,

    I got some help from a colleague on this so I'd like to amend my previous post. The LM1558 is a dual LM741 without trim pins so you can use any LM741 model as a drop-in replacement.

    For some additional information on the LM10, take a look at this app note: www.ti.com/.../snoa638a.pdf
    Are you using the 45V version or the 7V version?

    It was also pointed out to me that the LMC7111 is a CMOS device and the LM10 is bipolar, so using the LPV321-N will be a better fit for modeling the bias currents.

    If you would accept my friend request, we can take this conversation offline if you'd like to discuss some details.

    Best,
    Paul
  • 0 in reply to Paul Goedeke
    Intellectual 515 points

    Hi Paul, sorry for the delay.  Thanks for the help on this.  I have some followup.  I pasted your text and answered in line.


    For some additional information on the LM10, take a look at this app note: www.ti.com/.../snoa638a.pdf
    Are you using the 45V version or the 7V version?  I am using the 45V version. 

    ......the LMC7111 is a CMOS device and the LM10 is bipolar, so using the LPV321-N will be a better fit for modeling the bias currents. I am using the 45V version of LM10 (+/- supply connected to +27V, -8V, so in real life, LPV321 won't work.  I tried it in simulation, and it is not working correctly (not regulating a MOSFET to 10V), so I assuming it is virtually letting the smoke out.   I had an OPA364 in there as a placeholder, and that op amp was working correctly.  I think I am ok with the OPA364 right now... I'm not doing anything fancy with the circuit except creating a 10V reference.

  • 0 in reply to Scott Miller1
    TI__Mastermind 30600 points
    Sounds good. Let me know if you have any further questions.

    -Paul