The STMicroelectronics LD57100 is a high accuracy voltage regulator, which provides 1 A of current. It is equipped with an NMOS pass transistor, whose gate is biased by a dedicated pin, thus allowing the ultra-low drop performance even at very low input voltages.

Input voltage from VOUT to 5.5 V
Input bias supply pin from 3.0 V to 5.5 V
Ultra low-dropout voltage (40 mV typ. at 1 A load)
Low ground current (35 μA typ. at no load)
Output voltage tolerance: ±1% all over temperature range, ±0.5% at 25 °C