zitron:
The RF22 only draws 85mA at full power, plus maybe 20mA for the atmega. Also the transmission only happens in quick bursts so it's not always on. The mic5205 should be plenty, since servos are powered separately from the BEC. I think any regulator will work as long as the drop out voltage is not much more than 1V, obviously lower is better to prevent brownouts.
Thanks! you gave a very clear answer :D...Why does flytrons TX module have 2 vregs, mic5205 and a LM2937?