LTC1844 Series 150mA, Micropower, Low Noise, VLDO Linear Regulator UFEATURESDESCRIPTIO ■ Very Low Dropout: The LTC®1844 Series are low noise VLDOTM (very low 90mV at 150mA dropout) linear regulators designed for low power/portable 30mV at 50mA (LTC1844-3.3) applications. These regulators can operate from input ■ Wide Input Voltage Range: 1.6V to 6.5V voltages as low as 1.6V. Typical output noise is only ■ Low 35 µ A Supply Current, Even in Dropout 30µVRMS and typical dropout for the LTC1844-3.3 is just ■ Low Noise: 60 µ VRMS (10Hz to 100kHz) 90mV at the maximum load current of 150mA, reducing to ■ ± 1.75% Voltage Accuracy Over Temperature, 30mV at 50mA. Voltage and Current Ranges The internal P-channel MOSFET pass transistor requires ■ Fast Transient Response no base current, allowing the device to draw only 35µA ■ 10nA Supply Current in Shutdown during normal operation, independent of the dropout ■ Fixed Output Voltages: 1.5V, 1.8V, 2.5V, 2.8V, 3.3V voltage and load current. The quiescent current falls to a ■ Adjustable Output Voltage: 1.25V to 6V negligible 10nA during shutdown. ■ Output Current Limit ■ Reverse-Battery and Reverse-Current Protection Other features include high output voltage accuracy, ■ No Protection Diodes Needed excellent transient response, stability with ultralow ESR ■ Stable with 1µF Output Capacitor ceramic capacitors as small as 1µF, reverse-battery and ■ Stable with Ceramic Capacitors reverse-current protection, short-circuit and thermal ■ Short-Circuit and Thermal Overload Protection overload protection and output current limiting. ■ Low Profile (1mm) SOT-23 Package The LTC1844 regulators are available in a low profile U (1mm) SOT-23 (ThinSOTTM) package. APPLICATIO S , LTC and LT are registered trademarks of Linear Technology Corporation. ■ Portable Instruments and Battery-Powered Systems VLDO and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. ■ Bluetooth/802.11 Cards ■ Cellular Phones ■ PDAs and Notebook Computers UTYPICAL APPLICATIOLTC1844-3.3 Dropout Voltage vs Load Current 120 Fixed Voltage Low Noise, VLDO Linear Regulator 100 VIN IN OUT VOUT 3.3V TO 6.5V 3.3V 80 1µF 1µF LTC1844-3.3 60 OFF ON SHDN BYP GND 0.1µF 40 DROPOUT VOLTAGE (mV) 1844 TA01 20 0 0 25 50 75 100 125 150 IOUT (mA) 1844 TA02 1844fa 1