View r1121n-series datasheet:

’99.7.13 LOW NOISE 150mA LDO REGULATOR R1121N SERIES OUTLINE The R1121N Series are voltage regulator ICs with high output voltage accuracy, extremely low supply current, low ON- resistance and high ripple rejection by CMOS process. Each of these voltage regulator ICs consists of a voltage reference unit, an error amplifier, resistors, a current limit circuit, and a chip enable circuit. These ICs perform with low dropout voltage and a chip enable function. The line transient response and load transient response of the R1121N Series are excellent, thus these ICs are very suitable for the power supply for hand-held communication equipment. The output voltage of these ICs is fixed with high accuracy. Since the package for these ICs are SOT-23-5 (Mini-mold) package, high density