ISL91108 High-Efficiency Buck-Boost Regulators Renesas Electronics ISL91108 High-Efficiency Buck-Boost Regulators are highly-integrated buck-boost switching regulators that accept input voltages either above or below the regulated output voltage. Unlike other buck-boost regulators, ISL91108 automatically transitions between operating modes without significant output disturbance. The devices are capable of delivering up to 2.7A output current (PVIN = 3V, VOUT = 3.3V), and provides excellent efficiency due to their 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 Renesas / Intersil ISL91108 High-Efficiency Buck-Boost Regulators are designed for standalone applications and support 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.