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Hi Team,
Customer found LM8261 AOL curve simulation result is different from attached in TINA Ref Design file.
I mainly compare the AOL value as below, can any expert verify this?
Thanks a lot!
Andrew
Not sure where you are getting that rightside curve Andrew,
I had some trouble with DC operating point in the file you attached set up for an Aol test - I dropped in the TINA V11 library model and it worked fine,
This test looks good to me, DC Aol is 90dB - taking the feedback load out might increase this if the Zol is very high. The 40dB point shows 17MHz GBP and Aol=0dB point shows good phase margin.
Here is the test file in V7 using the V11 library model.
Hello Michael!!!!
Missed you and hope you doing good and healthy.
I'm using below setup as a buffer config, where goes wrong? Thanks.
Andrew
Op-amp Stability Analysis (buffer break at Vin - LM8261).TSC
Hey Michael thanks!
I overlooked the load condition with 10k ohms, it does match with simulation.
Thanks a lot!
Stay healthy!
Andrew
Thanks Andrew, I went ahead and tried to check the model Zol, yes - it is in the 700k region at low F, that is probably an error, had some trouble with numberical chatter,
Fixed that here changing the LC values and probably more useful changing some options,
This is a transistor based model where the RRout Zol is largely the early voltage parameter,
Some of them do specify a reasonable VAF, but maybe the output stage uses those that do not where it defaults to ideal,