A low-dropout (LDO) regulator is a DC linear voltage regulator which can operate with a very small input–output differential voltage. The advantages of a low dropout voltage include a lower minimum operating voltage, higher efficiency operation, and lower heat dissipation. Low-dropout regulators work in the same way as all linear voltage regulators. The main difference between a LDO and non-LDO regulator is their schematic topology. Instead of an emitter follower topology, LDO regulators utilize an open collector or open drain topology.