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Mismatch between input pins of opamp between Capture and PSpice

John Davies
I have a library of opamps that I use for teaching, which includes capture symbols and pspice models. All worked well with release 16.2 but two problems have arisen in 16.3. The second is that the mapping between pins in capture and pspice does not work correctly for some opamps. The two inputs (inverting and noninverting) get mixed up. The template in Capture is a correct match to the "subckt" line of the pspice model; I have checked this carefully. The only explanation that I can think of is that the mapping between capture and pspice is done by "pin order" rather than the template, but I thought that was obsolete. This happened before in an earlier release of orcad but I can't find a note of the fix, nor can I remember. Sorry if this is the wrong forum for this problem.
  • Khurana

    What's the error message i.e. how do you know that the inputs get mixed up...?

  • John Davies
    Sorry, I should have made the symptoms clear. The circuit does not behave correctly; a simple amplifier shows positive feedback instead of negative feedback, for instance. It works correctly after the connections to the + and - inputs are reversed in the Capture schematic. Thus the circuit appears to have positive feedback according to the schematic, but behaves as though it has negative feedback.
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