The ISL91108 is a highly-integrated buck-boost switching regulator that accepts input voltages either above or below the regulated output voltage. Unlike other buck-boost regulators， this regulator automatically transitions between operating modes without significant output disturbance. This device is capable of delivering up to 2.7A of burst current （PVIN = 3V， VOUT = 3.3V）， and provides excellent efficiency due to its fully synchronous 4-switch architecture. No load quiescent current of only 27.5μA also optimizes efficiency under light-load conditions. Forced PWM and/or synchronization to an external clock may also be selected for noise sensitive applications. The ISL91108 is designed for standalone applications and supports a 3.3V fixed output voltage or variable output voltages with an external resistor divider. Output voltages as low as 1V or as high as 5.2V are supported using an external resistor divider. The ISL91108 requires only a single inductor and very few external components. Power supply solution size is minimized by a 2.34mmx1.72mm WLCSP and a 2.6MHz switching frequency， which further reduces the size of external components.