FQS4901TF is a low dropout linear regulator from ON Semiconductor, with a maximum output voltage of 4.5 V and a minimum dropout voltage of 0.2 V. It is designed to provide a cost effective solution for low power, low voltage applications, such as medical instrumentation, RF transmitters, and cellular phones. It features a quiescent current of 140 µA, low profile TO-263 package, and over-temperature protection. Its output voltage is adjustable, and it has a maximum output load current of 200 mA.