The AP131 is a 300mA, fixed output voltage, low dropout linear regulator. The Device included pass element, error amplifier, band-gap, current limit and thermal shutdown circuitry. The device is ON when the EN pin is set to logic high level. The characteristics of low dropout voltage and less quiescent current make it good for some critical current applications, for example, some battery powered devices. The typical quiescent current is approximately 50μA from zero to maximum load. Due to the internal flexible design, it results in extensively fixed output voltage versions and makes it convenient to use for applications. Built-in current-limit and thermal-shutdown functions prevent any fault condition from IC damage. An external capacitor can be connected to the BP pin and reduce the output noise.