This paper presents a monolithic dual phase 2:1 DC-DC converter featuring a 2.0-2.5 V input range, employing quasi-resonant regulation and using LC resonant tanks with coupled inductors. The output voltage can be regulated in the 0.8 - 1 V range by regulating the ON-time of the switches, while the switching frequency corresponds to the resonant frequency of the LC tanks (160 MHz). The usage of air-core inductors and exclusively MOM capacitors leads to a cost-effective implementation. The proposed converter has been validated through a 3.45 mm2 (2.15 mm x 1.6 mm) fully integrated prototype implemented in a 28 nm CMOS process. Experimental results demonstrate a load current capability of 225 mA and a peak full load efficiency of 77.9 % at 2.5 V input and 1.0 V output. Performance analysis reveals comparable efficiency, efficiency enhancement factor (EEF) and power density with the current state of the art. The presented converter can be used as the basis for a family of modular monolithic DC-DC converter, as more power stages can be stacked to increase the conversion ratio.
