Hy there.

Recently i got challenged to build a differencial probe with 10x attenuation, 1MHz BW using a low cost op amp. I alreay unerstood the attenuator but im still stuggling with the op amp feedback compensation, i read some articles but cant quite understand what im doing wrong, can someone pls help me and explain what is going on? the hase goes like crazy and cant understand where is the problem

 

Please post your SPICE files. It is hard to see the little pictures.
Is it 1mhz or 50mhz?

 

The minimum requirements are 1 MHz but if it is possible i would love to get more BW. I just cant figure out how to compensate, the best results that i got where 20 Db and 40º phase shift

 

Looking at the data sheet 50mhz will not happen. 30mhz yes.
I put, across R3 a capacitor of 3pF to 2.2pF cap.

 

Can you explain how have you dimensioned that? and also how have you dimensioned the op amp feedback resistors?

I have done it in the model that i have sent you and nothing happend, cant understand it...

 

I put, across R3 a capacitor of 3pF to 2.2pF cap.

You need a capacitor across R3 and R13. Sorry.
Look at the data sheet.

This high-speed op-amp is not like others. This graph is important.

 

Thanks a lot for your time, friend. It really helped me a lot.

It will take some time to design the PCB and properly test it, but as soon as I have done it, I will let you know my feedback and the design files in case you are interested in building a similar one.

 

One thing I learned from building a similar circuit long time ago, is that parasitics have a large influence. Keep the board traces tight, and I mean tight. SMT components work much better than THT. And order a few other values of the compensation caps close to the intended value of 2.2pF.