OPA858-Q1: OPA858-Q1

Part Number: OPA858-Q1
Other Parts Discussed in Thread: OPA858, OPA859-Q1, PSPICE-FOR-TI, TINA-TI

Tool/software:

Subject: Query Regarding SPICE Model Issues in Simulation

Dear Technical Support,

I am currently working with the [Op-Amp Model, e.g., OPA858] in LTspice and have encountered several error messages in the simulation despite ensuring all connections are correct. The specific errors include nodes reported as floating and issues with convergence, which I've tried addressing by verifying the model and configurations without success. I am getting the output plots at the same time i am getting the spice errors also..

Attached are the error logs and the schematic I am using. I am concerned about potential issues these errors might indicate for the physical implementation on a PCB, as I plan to incorporate this op-amp in a design that is crucial for my project. Could you please provide guidance on whether these errors can impact the final application, or if there are any recommendations for adjustments or updates to the model?

same thing happens with OPA859-Q1 also 

Thank you for your assistance.

Best regards, 

Deepthi,

  • Hello Deepthi,

    TI recommends using TINA-TI or PSPICE-FOR-TI to simulate op amp models.  The models are designed for these simulators and are not designed or tested for LTSPICE compatibility. 

    If you are unable to simulate in TINA or PSPICE, there are threads and posts about converting a SPICE model to work with other simulators.  Editing model files is not recommended, but you may do so if you accept the risk of errors.

    I also recommend trying different resistor values and adding termination resistors (1TOhms) to nodes which are floating or do not converge.  Simulators need additional circuitry to force the mathematical calculations to result in real answers, which would not be necessary on a physical PCB (physics matters there).

    I am also unable to assist by using LTSPICE simulations, so it is difficult for me to use competitor models when debugging your circuit.  

    Best,

    Alec