Abstract-This paper presents the design and implementation of a new integrated circuit (IC) that is suitable for driving the new generation of high-frequency GaN HFETs. The circuit, based upon a resonant switching transition technique, is first briefly described and then discussed in detail, focusing on the design process practical considerations. A new level-shifter topology, used to generate the zero and negative gate-source voltages required to switch the GaN HFET, is introduced and analyzed. The experimental measurements included in this paper report the results of tests carried out on an IC designed and fabricated as part of the multiproject die in high-voltage process H35B4 of Austriamicrosystems. They fully demonstrate the performance of the proposed driver that opens the possibility of fully exploiting the wide capabilities and advantages of GaN devices for use in power electronics applications.Index Terms-GaN HFET, gate driver integrated circuit (IC), high frequency.