piotr_jan
Junior Member level 2
Hi Guys.
I am working on my hobby project - an oscilloscope based on ST Nucleo 446RE board. Everything is working fine and the project is progressing quickly. Unfortunately I am absolutely useless when I have to design something analogue. I need fast input buffer. In first prototype version I used 10MHz 10V/us OpAmp, and everything worked as I expected.
The Input signal 31.3KHz PWM signal generated by Atmega, divided by 2 (amplitude) using a resistor divider.
Here is the original signal without an input buffer:
https://youtu.be/EtVqZZmy5I0
Today I have received fast OpAmps with much higher slew rate (about 200v/us) and I hoped that the signal will have more square shape. And it actually
has, but I got a lots of noise form the opamp:
https://youtu.be/7ieETZmmcng
Inverting input is connected directly to the output. Single supply +5V.
What is the problem. Any help appreciated.
Cheers
Peter
I am working on my hobby project - an oscilloscope based on ST Nucleo 446RE board. Everything is working fine and the project is progressing quickly. Unfortunately I am absolutely useless when I have to design something analogue. I need fast input buffer. In first prototype version I used 10MHz 10V/us OpAmp, and everything worked as I expected.
Here is the original signal without an input buffer:
https://youtu.be/EtVqZZmy5I0
Today I have received fast OpAmps with much higher slew rate (about 200v/us) and I hoped that the signal will have more square shape. And it actually
has, but I got a lots of noise form the opamp:
https://youtu.be/7ieETZmmcng
Inverting input is connected directly to the output. Single supply +5V.
What is the problem. Any help appreciated.
Cheers
Peter