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While the SPICE models for the bipolar (LMxxxx) op amps work fine, the CMOS (LMCxxxx) op amp models do not converge. Is there a SPICE option that needs to be changed?

April 26, 2017amps bipolar CMOS Fine models op spice

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While the SPICE models for the bipolar (LMxxxx) op amps work fine, the CMOS (LMCxxxx) op amp models do not converge. Is there a SPICE option that needs to be changed?

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To correctly model the input bias current, the CMOS op amp SPICE models require a change to the default GMIN option setting on most SPICE packages. There is a comment about this on the op amp SPICE models web page, and also a few lines down in the model file. Set .OPTIONS GMIN=1E16 to model the ultra-low input bias current and improve convergence. In the simulation environment of Amplifiers WEBENCH, this option statement is correctly set..