In this paper, the characteristics of a micro DC-DC converter for portable electronic equipments are described. In the converter, an inductor, switching devices and control integrated circuits (ICs) were integrated. The external size of the converter module was 3.0 mm 3.0 mm 1.0 mm. And the converter had a high efficiency of 83% at the input voltage of 7.2 V and the output voltage of 1.5 V. The miniaturization of the converter was achieved by developing a small inductor of the size of 3.0 mm 3.0 mm 0.525 mm. High efficiency was achieved by adopting 0.6 µm CMOS process for ICs and switching devices, using N channel MOSFET for a high side power switch, and controlling a dead time adaptively. The efficiency characteristics of the converter were analyzed experimentally and theoretically. And the losses of the converter were theoretically analyzed.