The TPS79501-Q1 low-dropout (LDO), low-power linear voltage regulator features high power-supply rejection ratio (PSRR), ultralow noise, fast start-up, and excellent line and load transient responses in a small outline SON package. The device is stable with a small 1-µF ceramic capacitor on the output. The TPS79501-Q1 uses an advanced, proprietary BiCMOS fabrication process to yield extremely low dropout voltages (for example, 110 mV at 500 mA). The device achieves fast start-up times (approximately 50 µs with a 0.001-µF bypass capacitor) while consuming very low quiescent current (265 µA, typical). Moreover, when the device is placed in standby mode, the supply current is reduced to less than 1 µA. The TPS79501-Q1 exhibits approximately 33 µV_RMS of output voltage noise at 3-V output with a 0.1-µF bypass capacitor. Applications with analog components that are noise-sensitive, such as portable RF electronics, benefit from the high-PSRR and low-noise features, as well as from the fast response time.