Hello,
For an fpv application, I am using a video transmitter (TX5823) who needs 3.3V. I power it with a 1s lipo connected through a U1V10F3. The output is 3.3V but I have a lot of noise. With another power source I do not have this noise.
So the problem comes from the regulator.
I do not have this problem with another video transmitter (TX5813) who needs 5V and powered with U3V12F5
Can you recommend me another regulator?
I found those two: pololu.com/product/2842 pololu.com/product/2122
Problems like this are solved by properly filtering the power supply (the regulator output) and making sure all chips have decoupling capacitors (100 nF) as close as possible to the power pins.
To filter low frequency noise from the power supply, use a combination of high quality capacitors, typically 10 - 500 uF in parallel with 100 nF between V+ and ground. For high frequency noise, use RF chokes (ferrite beads on wires for very high frequencies) in series with the positive power supply lead, preceded and followed by 100 pF and 100 nF capacitors to ground.
Keep wires short and if you are planning a PCB, use a ground plane layer with decoupling capacitors on every chip.
