LP3991 Datasheet | National Semiconductor

Description Operating from a minimum input voltage of 1.65V, the LP3991 regulator has been designed to provide fixed stable output voltages for load currents up to 300m A. This device is suitable where accurate, low voltages are required from low input voltage sources and is therefore suitable for post regulation of switched mode regulators. In such applications, significant improvements in performance and EMI can be realized, with little reduction in overall efficiency. The LP3991 will provide fixed outputs as low as 1.2V from a wide input range of 1.65V to 3.6V Using the enable pin, the device may be controlled to provide a shutdown state, in which negligible supply current is drawn. The LP3991 is designed to be stable with space saving ceramic capacitors as small as 0402 case size. Performance is specified for a -40°C to 125°C junction temperature range. For output voltage options please contact your local NSC sales office. Features - - - - - - - - - - Operation from 1.65V to 3.6V Input 1% accuracy at room temperature Output Voltage from 1.2V to 2.8V 125m V Dropout at 300m A load 50µA Quiescent Current at 1m A Load Inrush Current controlled to 600m A PSRR 65d B at 1k Hz 100µs Start-Up time for 1.5V VOUT Stable with Ceramic Capacitors as small as 0402 Thermal-Overload and Short-Circuit Protection Package 4 pin micro SMD (0.963mm x 1.446mm) For other package options contact your NSC sales office. Applications - Post DC/DC Regulator - Battery Operated Devices - Hand-Held Information Appliances Typical Application Circuit © 2007 National Semiconductor Corporation .national. Pin Descriptions Packages Pin No. B1 Symbol VOUT Name and Function Voltage output. A Low ESR Ceramic Capacitor should be connected from this pin to GND. (See Application Information) Connect this output to the load circuit. mon Ground. Connect to Pad. Disables the Regulator when ≤ 0.4V. Enable Input has an internal 1.2MΩ pull-down resistor to GND. B2 VIN Voltage Supply...