Overview
Description
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. A 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. A power supply solution size is minimized by a 2.34mm x 1.72mm 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 the external component size
- Selectable forced PWM mode and external synchronization
- Fully protected from short-circuit, over-temperature, and undervoltage
- Small 2.34mm x 1.72mm WLCSP
Comparison
Applications
Documentation
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Type | Title | Date |
Datasheet | PDF 627 KB | |
Product Change Notice | PDF 182 KB | |
Application Note | PDF 592 KB | |
Application Note | PDF 509 KB | |
Application Note | PDF 397 KB | |
5 items
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Schematic symbols, PCB footprints, and 3D CAD models from SamacSys can be found by clicking on the CAD Model links in the Product Options table. If a symbol or model isn't available, it can be requested directly from SamacSys.

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FAQs
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Which is the best option between ISL91108 and ISL91110 for a high current buck-boost application?
Question:Between ISL91108 and ISL91110, which is the best option for a high current buck-boost application? Are they pin compatible? Answer: It depends on the maximum load current requirement of the application. ISL91108 can deliver 1.5A in boost mode (PVIN=3V, VOUT=3.3V). ISL91110 can deliver up ...
Jan 1, 1970 -
Can different inductor values/sizes be used with ISL91108/ISL91110 other than the ones recommended on the datasheet?
Question:Can different inductor values/sizes be used with ISL91108/ISL91110 other than the ones recommended on the datasheet? Answer:1uH inductors of other sizes can be used as long as the saturation current ratings meet the datasheet recommendation. Note that the efficiency and transient performance may be ...
Jan 1, 1970 -
What is the limiting current limiting factor for output current capability for ISL91108, ISL91110 and ISL91117?
Question:What is the limiting factor for output current capability? Answer:It depends on application circuit, input voltage and output voltage. Usually in buck-mode of operation, the inductor peak current limit is the limiting factor. In boost and buck-boost mode of operation, the typical cause is the intrinsic ...
Jan 1, 1970