On the recommendation of an SO-er, I'm looking at using a TPS54295 to power a controller that uses an ATMega 2560. The regulator will be powered by a 3-cell LiPo battery, implying input voltages between 9 and 12.4V. The controller will be in standby mode for a few minutes at a time, waking up periodically to check sensor states and perform various tasks. I expect the controller part of the circuit to draw 15-20mA when active, and 15-20uA when sleeping. Looking at the data sheet for the regulator, I'm seeing two things that concern me:
First off, there seems to be some amount of instability in the regulated voltage when the current draw goes below a hundred mAs or so:
Does this mean I need to consider a different regulator, does it not matter, or is this something that I need to rectify with additional passive components?
The second part is this section of the efficiency curve:
this tells me that when in standby, efficiency will drop into the low 20s or even 10s of %. Again - is this standard for this type of regulator (meaning I don't need to worry about it), or does this mean that I'll be burning it up at those levels?