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 300mA. 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 4.0V Using the enable pin, the device may be controlled to provide a shutdown state, in which negligible supply current is drawn.