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 1.2A
- High Efficiency: Up to 95%
- 35µA Quiescent Current Maximizes Light-load Efficiency
- 2.5MHz Switching Frequency Minimizes External Component Size
- Selectable Forced-PWM Mode and External Synchronization
- I2C Interface
- Fully Protected from Overcurrent, Over-temperature, and Undervoltage
- Small 3mm x 3mm TDFN Package
Description
The ISL9112 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.
The device is capable of delivering up to 1.2A output current and provides excellent efficiency due to its fully synchronous 4-switch architecture. A no-load quiescent current of only 35µA 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 ISL9112 supports a broader set of programmable features that may be accessed via an I2C bus interface. With a programmable output voltage range of 1.9V to 5V, the ISL9112 is ideal for applications requiring dynamically changing supply voltages. A programmable slew rate can be selected to provide smooth transitions between output voltage settings.
The device requires only a single inductor and very few external components. A power supply solution size is minimized by a tiny 3mm x 3mm package and a 2.5MHz switching frequency, which further reduces the size of external components.
Parameters
| Attributes | Value |
|---|---|
| Topology [Rail 1] | Buck-Boost |
| Outputs (#) | 1 |
| Input Voltage (Min) [Rail 1] (V) | 1.8 |
| Input Voltage (Max) [Rail 1] | 5.5 |
| Output Voltage (Min) [Rail 1] (V) | 1.9 |
| Output Voltage (Max) [Rail 1] (V) | 5 |
| Output Current (Max) [Rail 1] (A) | 1.2 |
| IQ [Rail 1] (µA) | 35 |
| Switching Frequency Range (Typical) (kHz) | 2500 - 2500 |
| Control Type | Current Mode |
| POR | Yes |
| SYNCH Capability | Yes |
| Peak Efficiency (%) | 95 |
| BOM Total Footprint (mm2) | 9 |
| Qualification Level | Standard |
Package Options
| Pkg. Type | Pkg. Dimensions (mm) | Lead Count (#) | Pitch (mm) |
|---|---|---|---|
| TDFN | 3.0 x 3.0 x 0.75 | 12 | 0.4 |
Applications
- Regulated 33V from a Single Li-Ion Battery
- Smart Phones and Tablet Computers
- Handheld Devices
- Point-of-Load Regulators
Support Communities
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ISL91127IR
Dear Technical Support Team, I am writing to request technical assistance regarding the ISL91127IRNZ-T chip, which we are currently using in our design. We have encountered a specific issue under the following operating conditions: Mode: Auto PFM Mode Input Voltage ($V_{IN}$): 3.8V Output Voltage ($V_{OUT ...
Mar 19, 2026 -
ISL91127IRAZ Datasheet error?
I am looking to using this buck/boost converter, ISL91127IRAZ, in a design that requires 5V from a LiPO battery. My plan was to use the ISL91127IRAZ because I can adjust it to output 5V. However when I read the datasheet for this device, see below, it says that ...
Jul 28, 2022 -
Max output current for ISL91127IRAZ under Vin=3.0V and Vout=5.0V
What's the maximum output current under Vin=3.0V and Vout=5.0V? Thanks.
Sep 3, 2024
Knowledge Base
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Which buck-boost regulators of the ISL91127 and ISL91128 families have an I2C interface?
Question: Which of these buck-boost regulators have an I2C interface? Answer: Of the products of these families, only the ISL91128 has an I2C interface. Another buck-boost regulator with I2C interface is ISL9112.
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Will the ISL91127 EN (enable) input work with 1.8V logic if the chip is powered from 5V?
Question: The datasheet for the ISL91127 specifies the VIH level logic threshold at 1.4V for the logic inputs when VIN = 3.6V. If I use the ISL91127 with VIN at 5V to 5.5V, will the EN logic threshold also go up? Will the EN input work reliably with ...
Support Communities
