Diodes Incorporated – 600mA DC-DC buck converter achieves high efficiency over full load range

Diodes DC-DC buck converters: automatic light-load algorithm

Diodes DC-DC buck converters: automatic light-load algorithm

The new AP3405 from Diodes Incorporated is a DC-DC buck converter which operates at high efficiency under light and heavy loads, helping system designers to extend battery run-times in mobile and wearable devices.

In quiescent mode, the converter draws a current of just 32μA, and its internal MOSFETs feature low on-resistance for reduced conduction losses under all load conditions.

Operating at a fixed switching frequency of 2MHz, the AP3405 allows for the use of small external components. Its U-DFN2020-8 package also has a small board footprint. A current-mode, synchronous buck converter, the AP3405 provides a fast response to transient voltage events, and offers cycle-by-cycle current limiting.

It operates from a 2.3V to 5.5V input-voltage range, and supplies an output ranging from 0.7V to 5.5V accurate to ±1.5%. It supplies loads up to 600mA.

Comprehensive protection features built into the AP3405 protect both the end system and the device itself.


  • Wearable devices
  • Battery-powered equipment

  • Up to 95% efficiency
  • Short-circuit protection
  • Under-voltage lock-out
  • Over-temperature protection
  • Over-current protection
  • Soft-start function