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TINA/Spice/THS4521: AC analysis does not support expression evaluation at each frequency.

DG47
Prodigy 40 points
Part Number: THS4521
Other Parts Discussed in Thread: TINA-TI,

Tool/software: TINA-TI or Spice Models

Has anyone else had an issue with this amplifier model in Cadence PSpice?  I'm trying to perform a frequency response analysis and i'm getting errors such as below: Note that the input is a VAC source with an amplitude of  1VAC.

INFO(ORPSIM-16573): AC analysis does not support expression evaluation at each frequency. ABM devices with non-linear operations will be evaluated only at bias point.

ERROR(ORPSIM-16550): Floating point computation failed during matrix solution. Possible solutions: 1)Ensure that all device parameters are in valid range. 2)Try using .options LIMIT

I've also tried a single sinusoid using a VSTIM source and I get the error below:

ERROR(ORPSIM-16550): Floating point computation failed during matrix solution. Possible solutions: 1)Ensure that all device parameters are in valid range. 2)Try using .options LIMIT

INTERNAL ERROR -- Overflow, Multiply

Any ideas?

  • 0
    TI__Intellectual 820 points
    Hi David,

    Please zip your PSpice project folder and share hereby.

    Thanks,
    Ahana
  • 0 in reply to Ahana Ghosh
    TI__Genius 9775 points

    Hi David,

    We did found that the THS4521 model has quite bit of convergence issue. We plan to debug and revisit this model. Unfortunately, due to our bandwidth and prioritization constraint, we will not be able to revisit this until around early March 2019. Sorry about this.

    Meanwhile, if you have your specific project/test bench case, as Ahana alluded, please post to this post so that we can include it for our QC testings purposes.

    Also attached is our old version of the model  from year 2009. We believe this model has better convergence, but somewhat less accurate when it comes to loading variation in the context of output impedance accuracy.

    THS4521_2009_04_02.LIB

    Herman