LDO (low-dropout regulator)
also: LDO · linear regulator
A simple linear regulator that gives a clean, low-noise output slightly below its input voltage; efficient only when the voltage drop across it is small.
An LDO regulates by dissipating the excess voltage as heat. It is quiet (no switching noise), cheap, small and simple, which makes it ideal for sensitive analog circuits, radios and references, and for small drops such as 3.6 V to 3.3 V. Its efficiency is roughly output voltage divided by input voltage, so dropping 12 V to 3.3 V wastes most of the power as heat.
"Low dropout" refers to the small minimum headroom between input and output it needs to stay in regulation. Quiescent current, the current the regulator itself draws, matters a great deal in battery products that sleep most of the time, and it varies by orders of magnitude between parts.
Founder takeaway
Use LDOs for small voltage drops and noise-sensitive rails, and check dropout voltage and quiescent current across your battery's full voltage range.
engineer review pending