I am trying to design a 4th order Butterworth low pass filter with the following parameters:
- cut off frequency at 20MHz to filter some noise on an input signal.
- I do not want any gain
- V+ = 3.3V and V- = GND
After calculation and simulation i came up with the following design using a pair of LT1886 OpAmp.
But when i connect this onto my design, it generates a lots of ringing on the input "IN1" and OpAmp output making the input and output signals even worse. When i disconnect the circuit, the input is pretty clean, so something is making my design goes wrongly.
Any input on how to improve the current design would be appreciated.