The RT9172 series of low-dropout linear regulators operate from a +2.25V to +6.0V input supply. A wide range of preset output voltage options is available. These low dropout linear regulators respond very fast to step changes in load, which are suitable for low voltage microprocessor applications. The RT9172 uses an internal PMOS as the pass device, which does not cause extra GND current in heavy load and dropout condition. The shutdown mode of low operation current makes the IC suitable for power-saving systems. The other features include current limiting and over temperature protection.