ISL91128

High Efficiency Buck-Boost Regulator with 4.5A Switches and I<sup>2</sup>C Interface

OVERVIEW

The ISL91128 is a high-current, buck-boost switching regulator for systems using new battery chemistries. It uses the Renesas proprietary buck-boost algorithm to maintain voltage regulation while providing excellent efficiency and very low output voltage ripple when the input voltage is close to the output voltage. The device also includes a selectable Bypass mode for low power consumption in applications that have a Sleep or Low Power mode.

The ISL91128 is capable of delivering at least 2.2A continuous output current (VOUT = 3.3V) across a battery voltage range of 2.5V to 4.35V. This maximizes the energy utilization of advanced, single-cell Li-ion battery chemistries that have significant capacity left at voltages below the system voltage. Its fully synchronous low ON-resistance 4-switch architecture and a low quiescent current of only 30µA optimize efficiency under all load conditions.

The ISL91128 supports a broader set of programmable features that can be accessed using an I2 C bus interface. With a programmable output voltage range of 1.9V to 5.0V, the ISL91128 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 ISL91128 is available in a 20 bump, 0.4mm pitch WLCSP (2.15mmx1.74mm) with a 2.5MHz switching frequency, which further reduces the size of external components.

KEY FEATURES

  • Accepts input voltages above or below regulated output voltage
  • Automatic and seamless transitions between Buck and Boost modes
  • I2C interface
  • Input voltage range: 1.8V to 5.5V
  • Continuous output current: up to 2.4A (PVIN = 2.5V, VOUT = 3.3V)
  • High efficiency: up to 96%
  • 30µA quiescent current maximizes light-load efficiency
  • Selectable bypass power saving mode operation
  • 2.5MHz switching frequency minimizes external component size
  • Fully protected for short-circuit, over-temperature, and undervoltage
  • Small 2.15mmx1.74mm WLCSP

BLOCK DIAGRAM

 Block Diagram

PARAMETRICS

Parameters
ISL91128
Basic Information
Production Status
Mass Production
Topology
Buck-Boost
# of Outputs
1
Input Voltage Min (V)
1.8
Input Voltage Max (V)
5.5
Output Voltage Min (V)
1.9
Output Voltage Max (V)
5
Output Current Max (A)
2.4
IQ
30 µA
Switching Freq. (max) (MHz)
2.9
Switching Freq. (min) (MHz)
2.1
Max Duty Cycle (%)
-
Qualification Level
Standard
Peak Efficiency (%)
96
POR
Yes
SYNCH Capability
No
Switching Frequency Range (MHz)
2.5
Can Sample
YES
Temperature Range
-40 to +85

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