I doubt that this UBEC (universal batteyr elimination circuit) is a buck-boost regulator since it needs at least 5.5V, but it lists a 93% efficiency, so it can't be a linear regulator either. And if it were a boost regulator I'd expect it to require a higher input voltage like all the rest I've found. Is this some kind of hybrid linear boost regulator? I have yet to find any chip with which I could make something similar, but I guess I'm gonna go back on Digikey shortly and have another look around.
It is a switching regulator, the link states that it uses a 300khz switching rate. Other features given are:
Features.
Over current and over heat protection.
Switching frequency 300khz.
Chip Efficiency is 92%. This UBEC utilises switching technology to gain a much higher efficiency than liniar BEC. Which means less heat and longer battery life.
The UBEC is equiped with a noise reduction alloy housing to reduce noise even further.
Incorrect polarity safety feature ensures the UBEC will not be destroyed should the battery be connected incorrectly.
All in all if that BEC works as rated you would have a hard time duplicating it at near that cost in any DIY project.
Lefty