Hi.
This is a novice type of question, I hope I don’t bore you all with it, but as I’m just getting into understanding op amp stability, I came across a graph in the data sheet of a OPA277 which I happen to have on my bench, and want to use in a test set up where the op amp is configured as an attenuator feeding into an ADC.
My loop gain simulation in TINA does not seem to correlate with the graph. In the cct design,
Beta= 10 /(10 + 1.25) = 0.9 or 20Log 0.9 = -1dB
where 1 / Beta meets the open loop gain. 1 / Beta is –20Log 0.9 = +1dB.
By the graph the phase margin is approx., -117 degrees.
How do I interpret this into the plot created by TINA. What is TINA showing phase margin or phase angle? plus why are all angles in the TINA plot positive? Does it look like I’m a bit confused??
BTW sorry if the formatting is off, with all the images imported.
Cheers
