Op-amp simulation

Maybe spice model is not 100% accurate ?

And you have not included parasitics in your schematic.

I would have guessed gain peaking but your Cload = 0 so thats out.


Regards, Dana.

Dear FreshmanNewbie,

FreshmanNewbie said:

Why is there a 60mV additional increase in the output voltage? Shouldn't it be the same 600mV?

Click to expand...

Even if the external load capacitance is not included in your test bench for the MCP660 op-amp, I examined its model and found it does include a 2 pf capacitance at its load. Hence, I suspect the reason you are observing a 60 mV increase in output amplitude with a 5 MHz input relative to the input amplitude and do not observe the 60 mV increase in amplitude relative to the input amplitude at 1 MHz is the transfer characteristic of the op-amp and its peripheral circuitry in your test bench.

Two options to attempt to confirm this hypothesis are:
1. Perform a small-signal AC analysis of your circuit with the input set to 1 V AC and observe the output voltage over frequency. This will illustrate the transfer function over frequency.
2. Apply a series of input frequencies and measure the gain at each frequency in a series of transient simulations to assemble the gain characteristic as a function of input frequency.

I hope this helps FreshmanNewbie!
Shawn

I agree, run an AC analysis. That should show any frequency peaking.