I am simulating a simple circuit with LTspice:
I was expecting V(NODE) to be 0 at all times as U1 is an ideal op-amp, but it seems it isn't.
How can I use an ideal op-amp?
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\$\begingroup\$ First you have to find one that is ideal (How can I use an ideal opamp?) <-- So, what's your real question --> How to make an ideal op-amp? Or, how to understand why an LTSpice ideal op-amp isn't ideal? \$\endgroup\$– Andy akaCommented Jan 13, 2023 at 21:11
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\$\begingroup\$ I just want to put an ideal opamp there, in the same way I put ideal resistors, capacitors and sources elsewhere in that circuit. I found out that this exact opamp behaves as ideal at low frequencies so there are probably some parameters to tune it but I cannot find them. \$\endgroup\$– user171780Commented Jan 13, 2023 at 21:17
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2 Answers
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The model of the opamp you are using gives similar results to LTspice's universalopamp device which means you are not using an ideal opamp model.
The simulation below shows the results with the gain bandwidth product (GBW) equal to 10MHz and 1000MHz. You can see the 10 MHz GBW is similar to your simulation and the 1000 MHz GBW is almost similar to @usser171780's simulation with using a truly ideal opamp.
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I ended up using the component e like this:
and setting Value=1e9
