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What's wrong with this opa?

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wjxcom

wjxcom

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Hi all: Please look at the OPA in the attachment, after I perform the TRAN analysis, I find the result is so strange!

From the AC analysis, the PHASE MARGIN is 60, and the BANDWIDTH is 40MHz, but from the TRAN analysis, I think this OPA is not stabilization! I do not know why???

Hi all, would you help me please? thanx!!!

 

could you please upload your schematic alone in paint or something.
 

    wjxcom

    wjxcom

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Did you run open loop or close loop? Notice that
OPA has high open loop gain, so even if you apply
very small input, the output will swing rail-rail,
looks like oscillation.
 

    wjxcom

    wjxcom

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i can't see you file
 

    wjxcom

    wjxcom

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plz upload with right format ur file
 

    wjxcom

    wjxcom

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where is your load ???

when you simualte ac ,you must add your load,because when add different load your stabilization is different.
 

    wjxcom

    wjxcom

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do not believe the AC analysis completely!!
tran analysis belong to large sigal
AC belong to small signal
 

Dear wjxcom,

Could you please attach your ac and tran simulation result as well. We can't do anything without looking at the plot. Thanks!
 

do not believe the AC analysis completely!!
tran analysis belong to large sigal
AC belong to small signal
 

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