Some of the important specifications of an LDO regulator are shown on this slide. Input voltage range is a voltage that may be applied to the input terminal; however, the minimum operating input voltage is output voltage plus dropout voltage or higher. Output voltage range can be from reference voltage to V_IN max – V_DROPOUT or a fixed value for fixed type. Dropout voltage is the voltage difference between input and output that is necessary to regulate the output. Ripple rejection ratio, also called PSRR, is the percentage of the ripples contained in the input voltage that is rejected from the output voltage. Finally, quiescent current is the difference between input and output current. Lower Q current of a system provides better efficiency for the system.