I just want make sure the D24V22F5 is appropriate to power RPi 3. I’m having some voltage droop issues, but that might be explained by my current bread board and 30awg jumpers set up. Assuming I’ve picked the right DC-DC converter, Should I be using a capacitor for smoothing? Is it OK to feed power to GPIO pins 2 & 6 or should I add a micro-USB jack to the power supply and feed the RPi the normal way? Thanks.
Update: The voltage droop problem has been solved. I was using some 30awg jumpers and it seems voltage drop through those jumpers were the problem. I was seeing voltages as low as 4.762v with the 30awg 10" jumpers. After relocating the D24V22F5 and switching to 22awg 3/4" jumpers, the voltage never got lower than 4.957v.
I’d still like to hear any recommendations on how to best power the RPi. Thanks.
Hi.
The D24V22F5 should be fine for most RPi applications. If your system has lots of peripherals powered off your RPi 3 or otherwise will be drawing near its 3A max, I recommend our higher power D36V28F5 regulator.
In general, you probably do not need any extra capacitors, but you could check with a scope to see if you are getting a lot of noise or dips. Either the GPIO header or USB connector is fine.
-Claire
Thanks for your help. I just needed to hear that I’m not doing something crazy. 
Rocky
Hi Clair - similar question for this part family.
I have this powered from a 12V supply with the 5V going to a small Arduino board. This works well under normal usage - the 5V is attached to the board through one of the pins.
My concern is when hooking up the Arduino to update the software. In this case, I usually power off the 12V so the Arduino is only getting its power through the USB - no problem.
However, if I want to debug, I need the 12V on. There will be contention between the USB 5V and the 5V from this D24V22F5.
Can I take advantage of the enable pin of the D24V22F5 to do this? If there is 5V from the USB, one could disable the output of the D24V22F5. This doesn’t seem clean enough. I’m currently using a 5V switch - your FPF1320. This works fine, but it is just mechanically clunky.
Just looking for slightly cleaner solution.
Thanks,
Steve
Hi, Steve.
It should be possible to disable the regulator to avoid the two 5V supplies fighting. What behavior did you see when you tried it? How were you controlling the EN pin? Could you post a schematic or wiring diagram and pictures of the setup where you were just disabling the regulator?
-Claire
You need to provide the RPI its rated input voltage to run it normally.