We are using your PFET Buck Controller LM3485 and have a few questions about noise problems and their solutions.
At 7.2 V – 7.4 V we are currently facing some noise problems on the input current.
The output voltage is 7 V.
In the attached files you see the measurements for 7.2 V and 7.4 V. This noise is noticeable by ear.
Is it possible to get rid of that noise by ESR?
We have been trying with a 50mOhm and 1.3 Ohm ESR but were not able to solve this.
We are using MLCC capacitors with Flexible Termination at the Output with 10uF each. (you can see in the attached schematic).
Is it possible to solve the problem by adjusting capacitor values at the feedback pin ?