STMicroelectronics – 6MHz, 500mA step-down converter ST1S15 offers valuable system space saving


ST1S15: very small supporting components for space-saving designs

STMicroelectronics’ ST1S15 is an efficient step-down converter which provides an output current of up to 500mA from an input voltage ranging between 2.3V and 5.5V.

The converter’s main benefits are its high efficiency, typically 85%, and the small footprint of the complete power-conversion circuit. Thanks to its high 6MHz switching frequency, the ST1S15 can operate with small supporting components: an inductor with a nominal value of 470nH, and an output capacitor of just 4.7μF. At the same time, the ST1S15 produces a very fast and accurate response to load and line transients.

The converter can operate in Pulse Frequency Modulation mode, for the highest efficiency under light-load conditions, or PWM mode for tight regulation and the best dynamic performance.


  • 45μA quiescent current
  • -1.5% typical regulation
  • 10mV output-voltage ripple in PWM mode
  • Short-circuit protection
  • Thermal protection


  • Power supplies for DSPs and multimedia processor cores
  • Mobile phones
  • PDAs