LTC1844

U U FEATURES ■ Very Low Dropout: 90mV at 150mA 30mV at 50mA (LTC1844-3.3) ■ Wide Input Voltage Range: 1.6V to 6.5V ■ Low 35µA Supply Current, Even in Dropout ■ Low Noise: 60µVRMS (10Hz to 100kHz) ■ ±1.75% Voltage Accuracy Over Temperature, Voltage and Current Ranges ■ Fast Transient Response ■ 10nA Supply Current in Shutdown ■ Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 2.8V, 3.3V ■ Adjustable Output Voltage: 1.25V to 6V ■ Output Current Limit ■ Reverse-Battery and Reverse-Current Protection ■ No Protection Diodes Needed ■ Stable with 1µF Output Capacitor ■ Stable with Ceramic Capacitors ■ Short-Circuit and Thermal Overload Protection ■ Low Profile (1mm) SOT-23 Package U APPLICATIO S ■ Portable Instruments and Battery-Powered Systems ■ Bluetooth/802.11 Cards ■ Cellular Phones ■ PDAs and Notebook Computers LTC1844 Series 150mA, Micropower, Low Noise, VLDO Linear Regulator DESCRIPTIO The LTC®1844 Series are low noise VLDOTM (very low dropout) linear regulators designed for low power/portable applications. These regulators can operate from input voltages as low as 1.6V. Typical output noise is only 30µVRMS and typical dropout for the LTC1844-3.3 is just 90mV at the maximum load current of 150mA, reducing to 30mV at 50mA. The internal P-channel MOSFET pass transistor requires no base current, allowing the device to draw only 35µA during normal operation, independent of the dropout voltage and load current. The quiescent current falls to a negligible 10nA during shutdown. Other fea...