TPS79430

TPS794xx www.ti.com SLVS349E – NOVEMBER 2001 – REVISED DECEMBER 2005 ULTRALOW-NOISE, HIGH-PSRR, FAST, RF, 250-mA LOW-DROPOUT LINEAR REGULATORS FEATURES 250-mA Low-Dropout Regulator With Enable Available in Fixed and Adjustable (1.2 V to 5.5 V) Versions High PSRR (60 dB at 10 kHz) Ultralow Noise (32 µVrms, TPS79428) Fast Start-Up Time (50 µs) Stable With a 2.2-µF Ceramic Capacitor Excellent Load/Line Transient Response Very Low Dropout Voltage (155 mV at Full Load) Available in MSOP-8 and SOT223-6 Packages APPLICATIONS RF: VCOs, Receivers, ADCs Audio Bluetooth™, Wireless LAN Cellular and Cordless Telephones Handheld Organizers, PDAs DESCRIPTION The TPS794xx family of low-dropout (LDO) linear voltage regulators features high power-supply rejection ratio (PSRR), ultralow-noise, fast start-up, and excellent line and load transient responses in small outline, MSOP-8 PowerPAD™ and SOT223-6 packages. Each device in the family is stable with a small 2.2-µF ceramic capacitor on the output. The family uses an advanced, proprietary BiCMOS fabrication process to yield extremely low dropout voltages (for example, 155 mV at 250 mA). Each device achieves fast start-up times (approximately 50 µs with a 0.001-µF bypass capacitor) while consuming low quiescent current (170 µA typical). Moreover, when the device is placed in standby mode, the supply current is reduced to less than 1 µA. The TPS79428 exhibits approximately 32 µVRMS of output voltage noise at 2.8 V...