Other Parts Discussed in Thread: OPA4188
Several TI documents reference Tim Green's 15-part series on Operational Amplifier Stability. I have done extensive web searches, and have managed to find a few parts piecemeal. Is the entire series available anywhere? Please advise. Thanks.
Hi!
I am using the "Rate-Of-Closure" Stability criteria (Part 1 of 4) to analyze some different opamp networks at different temperatures. A weird behavior is occurring at low temperatures, at -40°C using OPA4188:
In the plot above I am showing the loop gain graph for 25°C and -40°C. For the case of -40°C, since 1/beta is above Aol. My interpretation is: it means that there is no margin for Aol to fix 1/beta, so the circuit is unstable at -40°C, isn't it?
We have tested a small lot in the lab (not isolated but connected to some others) and in some cases it has shown to be unstable (not all times, in every circuit of the lot), so I am looking forward to substantiate theoretically why we are observing such behavior.
Thank you very much for your help.
