The VBIAS rail that powers the control circuit of the LDO draws very low current (on the order of the quiescent current of the LDO) and can be connected to any power supply that is equal to or greater than 1.4V above the output voltage. The main power path is through VIN, which can be a lower voltage than VBIAS; it can be as low as VOUT + VDO, increasing the efficiency of the solution in many power-sensitive applications. For example, VIN can be an output of a high-efficiency, dc-dc step-down regulator. The TPS720xx supports a novel feature in which the output of the LDO regulates under light loads when the IN pin is left floating. The light-load drive current is sourced from VBIAS under this condition. This feature is particularly useful in power-saving applications where the dc/dc converter connected to the IN pin is disabled but the LDO is still required to regulate the voltage to a light load. The TPS720xx is stable with ceramic capacitors and uses an advanced BICMOS fabrication process that yields a dropout of 110mV at a 350mA output load. The TPS720xx has the unique feature of providing a monotonic VOUT rise (overshoot limited to 3%) with VIN inrush current limited to 100mA + ILOAD with an output capacitor of 2.2F.