The purpose of a voltage regulator is to provide a fixed voltage to be delivered to a load. There are two types of voltage regulators: switching regulators and linear regulators. An LDO is a linear regulator. The most valuable characteristics of LDOs are low cost and the ability to provide super clean voltage without switching noise. On the downside, an LDO’s efficiency is not as good as a switching regulator’s, because the difference in the input and output voltage is dissipated as heat. The term, “dropout voltage” means the minimum difference voltage between VIN and VOUT. Therefore, lower dropout voltage means lower heat dissipation and higher efficiency.