Voltage regulator suggestions for ATmega328?

Hi everyone

I've been experimenting with a bare bones 328 chip, and I think I'm getting close to the point where I will be needing to connect it to a battery (so far I've been using my 5v USB power supply).

Specifically, I want to power my 328 with 5v from a 7.4v lipo battery. While the chip is "awake", it will be drawing less than 300mA. However, when the chip is sleeping, it will draw ~6uA.

My question is: what voltage regulators (step down?) would you recommend that would be able to power the Atmega328 while it is in standby mode while having the least amount of draw possible (to extend the battery lifetime as much possible)?

Thanks :slight_smile:

If you haven't seen it before, the classic description of how to save power in Arduino-like processors was written by Nick Gammon: Gammon Forum : Electronics : Microprocessors : Power saving techniques for microprocessors

Do you need to be running at 5v and coming down from a 7.4 two cell lipo? Perhaps you can run at 8Mhz or slower on 3.3-3.7v, and use a single cell 4.2-3.7 lipo?

Pololu.com has a series of switched regulators that are up to 90% efficient, and have shutdown modes: Pololu - Regulators and Power Supplies

Hi Mike

thanks for your feedback. I did see Nick's awesome power tutorial, which inspired me to start playing around with stand alone chips :slight_smile:

For my project I need to feed my chip with 5v, so that's why I need to use a 7.4v lipo along with some kind of switched regulator. I did look at the Pololu regulators you mentioned... would these still provide power to the chip even when it is in stand-by (i.e.: drawing 6.4 uA)? Or would this be such small of a power draw that the regulator will think there isn't anything attached to it? Just wondering...

Unless you actually wire up the enable pin, I don’t think these regulators go to sleep automatically. You have to explicitly tell them to go to power saving mode, at least that is the impression I got scanning the spec sheet.