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What's wrong with this opa?

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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!!!

 

amriths04

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

    wjxcom

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gte582w

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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

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kivvzhou

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i can't see you file
 

    wjxcom

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pmr9

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plz upload with right format ur file
 

    wjxcom

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wjlzhx

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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

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liuyonggen_1

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

pseudockb

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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!
 

jjsnail

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

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