The ISL91133 is an integrated boost switching regulator for battery powered applications. The device provides a power supply solution for products using a one cell Li-ion or Li-polymer battery. The device is capable of delivering up to 2.3A output current from VIN = 2.5V and VOUT = 3.3V. The no load quiescent current is only 108μA in Boost Mode and 45μA in Forced Bypass Mode， which significantly reduces the standby consumption. The ISL91133 offers a Bypass Mode operation where the output is directly connected to the input through a 38mΩ MOSFET to allow a significantly lower dropout voltage. The Bypass Mode can be entered by an external command， or by auto bypass. The Forced Bypass Mode allows the output voltage to operate close to the input voltage and improves the efficiency under these conditions. The ISL91133 is designed to support 6 fixed output voltages ranging from 3.15V to 5V. A voltage select pin is available for each output variant to scale up the output voltage by a small offset to compensate the load transient droop. The ISL91133 requires only an inductor and a few external components to operate. The 2.5MHz switching frequency further reduces the size of external components. The ISL91133 is available in a 16 bump， 0.4mm pitch， 1.78mm x 1.78mm WLCSP.