Needing a clean 5v reg

[David97]

Hi everyone. Working on building a small video receiver to use with FPV models.

Ive been playing with a rx5808 module. First I was using a arduino board to get 5v power from for testing. But this was not giving me enough current. The regulator was getting hot.

I measured the current to be around 200mA. I was dropping the voltage from a 12.6V battery.
That's (12.6-5)*0.2=1.5Watt, that's probably why it was getting hot.

So I took a cheap Chinese, no name, buck converter from my box of parts, and hooked that into it. Problem was that even with a 470uf cap, was producing noise (I think, I dont have a scope). Anyway the video sucked compared to my other receiver (store bought), which I'm certain uses the same module.

So cant definativley prove that that was the problem without a scope, but not going to want to run the cheap anonymous buck regulator from china anyway. I know having low ripple is important with this project anyway.

So weather or not that was the problem, I need a new 5v regulator.
Needing something with low ripple, has a input range of 6V-12.6V, and can provide the necessary current.

Switching would be nice, but not necessary, since I know switching regs tend to produce more noise.

Thanks for your're help! Sorry for the noobie nature of this question

[David97]

Discussions on this thread about a similar project have led me to believe that this would be a good option

http://www.rcgroups.com/forums/showthread.php?t=2477752&page=11


http://nz.rs-online.com/web/p/switching-regulators/6664379/

[homebrew]

Hm, why not using a good old 7805 linear regulator in a TO220 case?
200mA doesn't seem to be a big deal - just select a proper heat sink.

Add two 100nF bypass caps (input and output) and a 470uF bulk capacitor at the input and another 100uF on the output and you should be fine. A 1N400X diode as reverse bias protection and another one to protect from reverse polarity.

Adding a fuse would make it even more safe.

However, this won't work anymore with 6V. You probably need something around 8V to get this working ...

[JPortici]

+1
i will be using the same configuration in a future project. i am basically a noob in smps but it wasn't hard to achieve good-ish performance, maybe with poor efficiency but a rather clean signal

blueskull might correct me but i wouldn't go crazy high in switching frequency as LDO PSSR usually become rather poor over 10-20 kHz