Because my project need 24 voltage output, output voltage cascade such as every 4V, The 24 cascade is 4*24=96V.
Every output voltage is solation voltage+DAC( because the small ouptut current of DAC, the output driving current I need is 150mA at least). So here I chose OPA551UA to be the volloge follower to increase driving.
I texted the board which I have drawn, however,I found that if the voltage of 6~7 over 4V,( output shows oscillation waveform ); while when here just 4 has the voltage output( 4V and others keep 0V ),the output has no any osillation.
The wave is as following:
![](https://forum.evilmadscientist.com/uploads/editor/pr/6nu3fsgv48sh.jpg “”)
![](https://forum.evilmadscientist.com/uploads/editor/be/wq3n3olbbh9b.jpg “”)
![](https://forum.evilmadscientist.com/uploads/editor/kj/3brf5ic840kb.jpg “”)
According to the [dataheet of OPA551UA](http://www.kynix.com/uploadfiles/pdf65976/OPA551UA.pdf “dataheet of OPA551UA”), I have tried to add R1 and R2(10K), Gain=2,but the problems still didn’t be solved ! In addition, I also have tried to add a 1ohm resistance in the output,but it’s still useless!
Who can help me ? Thanks in advance !