The RP102x Series are CMOS-based voltage regulator ICs with high output voltage accuracy, extremely low supply current, low ON-resistance, and high ripple rejection. Each of these ICs consists of a voltage reference unit, an error amplifier, a resistor-net for voltage setting, a current limit circuit and a chip enable circuit. These ICs perform with low dropout voltage and "chip enable" function. The line transient response and load transient response of the RP102x 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 packages for these ICs are SOT-23-5, PLP1820-6, and WLCSP-4-P2, therefore high density mounting of the ICs on boards is possible.