Intersil – ISL8117: New Controller Enables Single Stage Buck Converter Designs for Very High Input/Output Ratios

The new ISL8117, a 60V synchronous buck controller from Intersil, provides a simple, low cost and efficient way to implement a point-of-load (PoL) power supply in which there is a large difference between the input and output voltages.

The ISL8117 can provide stable operation with a remarkably low on-time of as little as 40ns. This enables the designer to create a power supply with a very low duty cycle, such as a PoL circuit which steps a 48V input down to a 1V output.

Before now, the designer of such an application would have to choose one of two options: an expensive module, or a two-stage discrete DC/DC converter circuit. The ISL8117 enables this wide voltage gap to be bridged for the first time by a single stage converter design. This is cheaper than a module, and both cheaper and easier to design than an equivalent two-stage design.

In addition, the ISL8117 provides high efficiency across all loads. Its unique diode emulation mode dramatically lowers light load power consumption while producing consistent output ripple at varying load levels.

In ideal situations, a complete power supply circuit can be designed with the ISL8117 and just 10 external components.

The device uses internal loop compensation, and provides single-resistor settings for functions such as operating frequency and over-current protection. Its current mode control scheme with input voltage feed-forward enables it to support various applications even with fixed internal compensation schemes.


  • Switching frequency adjustable between 100kHz and 2MHz
  • Up to 98% conversion efficiency
  • ±1.5% output voltage accuracy
  • Programmable soft start
  • Power good indicator

  • Industrial equipment
  • Networking and communications equipment
  • Medical equipment
  • Industrial process control equipment


Development Board
Part supported: ISL8117
The ISL8117EVAL2Z development board provides a comprehensive platform for exploration of the ISL8117’s ability to step a power rail of as much as 48V down to as little as 1V.