Photodiode falltime problem

[pooya_BA]

hi
I studied the order of gain amplifiers

This method was written on the site below to reduce noise.

https://www.edn.com/low-noise-ac-amplifier-has-digital-control-of-gain-and-bandwidth/

I changed the order and my results are as follows.

As you can see, the wave does not have its previous shape.
Risetime and falltime have also increased.

 

[KlausST]

Hi,

You again modify things (gain) which I did not recommend. And you don't tell why.

... Then you see that the result is worse. --> Yes, as expectable.

Klaus

 

[pooya_BA]

Hi there
In the above simulation, the only change than I have done is increasing the resistance to have a higher gain. I did not understand if you pointed out to this change or you meant something else. Please let me know in detail what I need to change.

 

[KlausST]

Hi,

only change than I have done is increasing the resistance to have a higher gain.

But why? For sure changing the gain will modify timing and waveform.
We are now at post #44. Two and a half weeks...
Ask yourself: Does it improve circuit performance? Does it speed up progress? Does it motivate to help?

Klaus