Intersil – Efficient new buck-boost regulator for battery-powered portables carries up to 3A


Intersil has launched the ISL91127IR buck-boost regulator which offers high conversion efficiency up to 96% and a high current capability.

Supplied in a QFN package, the regulator has a compact footprint which makes it ideal for use in battery-powered and portable devices. In addition, it offers a low quiescent current of 30μA for superior light-load efficiency. It includes on-board power MOSFETs rated for a maximum current of 4.5A.

In hand-held devices, in which the input voltage might at different times be higher or lower than the output voltage, a buck-boost regulator improves efficiency and provides longer battery run-time than a circuit based on a boost regulator plus bypass.

The ISL91127IR operates in buck, boost or buck-boost mode, depending on the relation between input and output voltages, and provides smooth transitions between modes to prevent noise and glitches.

The new buck-boost regulator’s wide input- voltage range of 1.8V-5.5V makes it suitable for various battery topologies. The part’s output voltage ranges between 1V and 5.2V.

The ISL91127IR provides for dynamic adjustment of the output voltage. Programmable over an I2C interface, this feature eliminates the need for feedback resistors and allows the re-use of the same hardware design in products with different output voltages.


  • Output current up to 3A in boost mode
  • Under-voltage, short-circuit and thermal protections
  • 2.5MHz switching frequency


  • Handheld and battery-powered consumer and medical devices
  • Wireless communications devices
  • RF power amplifiers



The ISL91127IRN-EVZ and ISL91127IRA-EVZ platforms enable quick evaluation of the features of the ISL91127IR buck-boost regulator series. The ISL91127IRA-EVZ has a programmable output voltage, and the ISL91127IRN-EVZ has a fixed 3.3V output voltage.

Orderable Part Numbers: ISL91127IRN-EVZ, ISL91127IRA-EVZ