Aimed at use in space-constrained mobile and ultra-portable devices, the FAN5665 is a high-efficiency 30mA adaptive charge pump boost converter in a compact 1.21x1.21mm WL-CSP package. For USB-enabled devices needing a 5V I/O rail, this converter chip provides an optimal quick-fix solution. Thanks to its 0.625mm profile and the fact that it does not require a bulky inductor, it offers a slim solution for applications with limited space. It achieves up to 92% efficiency and can support an input-voltage range of 2.9 to 5.5V. In addition, the switches are pre-buffered to provide a low in-rush current, which results in minimised noise on the supply line.