LTspice: Stability of Op Amp Circuits
We all know that feedback circuits can oscillate. We may even know some tricks of how to fix it. But wouldn’t it be nice if our simulation tool could show us exactly what is happening, and why?
This video illustrates how to use the .AC analysis to look at open loop gain and phase of operational amplifier feedback circuits in LTspice.
It explains how to break the feedback loop in an op amp circuit while maintaining the correct operating point so that the plot the open loop transfer function of the circuit can be obtained and the phase margin measured.
This video also covers some common techniques on how to improve the phase margin of a design and build your circuit intuition.