Regulator Recommendation For 3.3v Application

After looking over all the Pololu buck converter families, I am a bit overwhelmed. In terms of criteria, I have an ultra-low power application running a bare bones Atmega 32U4 . Most of the time, the micro is asleep, but when woken, it can generate a max of 400mA. I have been running off my bench supply and would now like to move it to a battery-operated fixture. From a power source perspective, it will run off 6 AA batteries in series, for a total of 9V.


  • Power min: ~3.3v
  • Power Max: ~9V
  • Max current: 400mA

I am trying to find a suitable buck converter to step down the ~9V power supply to a steady 3.3v, with maximum efficiency in mind. I am looking for a possible recommendation based on the criteria above. I have picked out two, namely the S7V8F3 or the D24V5F3, but maybe there’s another one out there that I missed.

Note that I did look at dropping the bare 32U4 idea and just using the A-Star 32U4 Micro, but I think that uses a linear regulator opposed to switching. Also, I would have to mod the board to pull out unneeded LED’s and such. It’s still an option, if that makes more sense.


Hello, Bert.

The D24V5F3 is probably our best option for your application. By the way, you might also consider our A-Star 32U4 Mini controllers as they feature integrated switching regulators:

Out of curiosity, can you tell me more about your project?