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Hello Ikuo-san,

I am glad my explanation was able to assist you.  If you ever have any additional questions regarding high-speed parts, please know you can always ask here.

Best Regards,

Alec  

Hello Alec-san,

Thank you for your reply.

I failed to attach the figure, however I am very satisfied with your answer.

The detailed explanation of 1) was very helpful.
Also, thank you for agreeing to 2).

Best Regards,

Ikuo

Hello,

The questions you asked are good ones to discuss, I will do my best to help below.  I have a shorter section at the bottom with less explanation.  Also, your images you attached did not post/are not visible.  If you would like, you could repost/edit…

Hello Sima,

Thank you for your reply. I could simulate of OPA859.

Your answers and training videos were very helpful.

Thank you very much,

Ikuo

Hello Ikuo,

   It looks like the OPA859 is one of TI devices that has not yet been loaded into Pspice for TI. I believe they are working on importing all TI models into this software. In the meantime you can import the OPA859 .lib file into Pspice for TI…

Hello Andrea,

Kai's simulations should give you an idea of what to expect for transient simulations. I don't think the OPA857 is the correct device to use here as an integrator since the feedback is limited to either 20kohms or 5k-ohms. You can use the…

Hello George,

Please use the 1.8fA/rtHz of the OPA659 as an initial flatband number of the current noise that will rise over frequency. Current noise at 10MHz will be closer to the magnitude of the OPA859 rather than 1.8fA/rthz.

Best,

Hasan Babiker

If that is the case, the OPA659 data sheet is way off because it shows a current noise of 1.8fA/rtHz at 10MHz whereas the OPA859 has ~0.8pA/rtHz at 10MHz.  Which one am I supposed to believe?  Or are they both wrong?

Hello George,

The plot on the OPA859 datasheet is a more accurate representation of how the current-noise will behave on the OPA659.

Best,

Hasan Babiker

The plot in the OPA859 data sheet is what prompted me to ask the question.  It is not clear to me if it applies to CMOS transistors only or if it applies to JFETs as well.  Figure 22 in the OPA659 data sheet shows the current noise constant up to 10MHz…

Incidentally, the OPA859 is one option - 

I see this plot in the OPA859, certainly a designer sim and not likely in the TINA model,

TheOPA659 might be similar but only a designer sim would tell, 

Hi Daniel,

the simulation follows the datasheet:

Kai

Hi kai, 

any Idea why I'm seeing clipping at the output when I increase the amplitude of the signal? With a signal of amplitude 20m, I'm seeing clipping at 2.4V. I would have expected a peak of 2.65V.