The ISL91110 is a high-current buck-boost switching regulator for systems using new battery chemistries. It uses Intersil’s proprietary buck-boost algorithm to maintain voltage regulation while providing excellent efficiency and very low output voltage ripple when the input voltage is close to the output voltage. The ISL91110 is capable of delivering at least 2A continuous output current （VOUT = 3.3V） over a battery voltage range of 2.5V to 4.35V. This maximizes the energy utilization of advanced single-cell Li-ion battery chemistries that have significant capacity left at voltages below the system voltage. Its fully synchronous low ON-resistance 4-switch architecture and a low quiescent current of only 35μA optimize efficiency under all load conditions. The ISL91110 supports standalone applications with a fixed 3.3V or 3.5V output voltage or adjustable output voltage with an external resistor divider. Output voltages as low as 1.0V or as high as 5.2V are supported. The ISL91110 is available in a 25-bump， 0.4mm pitch WLCSP （2.33mmx2.07mm） and a 2.5MHz switching frequency， which further reduces the size of external components.