This little buck converter based on the TPS62827 is super handy, taking up to 5.5V input and providing a 3.3V output with up to 2A current. It's great for supplying power to hungry 3.3V voltage circuits from a range of battery or power options. This chip provides up to 2 Amp load current across the entire input voltage range of 3.4 to 5.5V. It's not a huge range but does cover LiPoly batteries, 3 alkalines, and USB power.