rf_man
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Hi gurus,
Please see the attached bode plot of the loop gain of a certain circuit, it's made by spectre stb analysis. From the plot, it can be seen that at 0db points, the loop phases are respectively 96 degrees and -100 degrees, so the phase margins are 276 degrees (or -84 degrees), -80 degrees, respectively, right? The phase margins are both greater than 60 degrees, therefore the loop should be stable. But from transient simulation, the circuit oscillates, what's wrong?
I don't have experience with stability issues, if the question is stupid, please don't laugh at me. Thank you in advance for your feedback.
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