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.

Features

• Accepts input voltages above or below regulated output

voltage

• Automatic and seamless transitions between buck and

boost modes

• Input voltage range: 1.8V to 5.5V

• Output current: up to 1.6A DC (PVIN = 2.8V, VOUT = 3.3V)

• Burst current: up to 2.7A (PVIN = 3V, VOUT = 3.3V, tON

<600µs, t = 4.6ms)

• High efficiency: up to 95

• 27.5µA quiescent current maximizes light load efficiency

• 2.6MHz switching frequency minimizes external component

size

• Selectable forced PWM mode and external synchronization

• Fully protected for short-circuit, over-temperature, and

undervoltage

• Small 2.34mm x 1.72mm WLCSP

Applications

• Smartphones and tablets

• Wireless communication devices

• 2G/3G/4G power amplifiers