Low-dropout (LDO) regulators are a simple, inexpensive way to provide a regulated output voltage powered from a higher voltage input. An LDO regulator can regulate the output voltage even when the supply voltage is very close to the output voltage. For instance, it’s able to generate 3.3 V from a 3.6-V Li-on battery. Such regulators are easier to implement than switching converters, and unlike switching regulators, LDOs don’t create high levels of switching noise.
Choosing the right LDO can be critical to maximizing an application’s performance. Low-noise LDOs help ensure a clean dc power supply. It is, as a result, important to both select an LDO with low-noise properties as well as implementing techniques to ensure the cleanest output possible.