In this article, the proposed monolithic gallium nitride (GaN)-based driver uses the diode-emulated technique to reduce reverse conduction through a meta-stable fast (MSF) comparator with sub-0.2-ns deadtime. In addition, an active bootstrap controller with a fast discharge loop is used to reduce parasitic effects to improve the driving capability, thereby increasing the switching frequency. Furthermore, the proposed gate driver with dual $dv/dt$ control can reduce the gate-ringing during turn-on/turn-off. Experimental results show that the GaN-based monolithic driver can achieve an operating frequency of 50 MHz and a slew rate of 120 V/ns. At 50 MHz, the conversion of 48-to-5 V can achieve a peak efficiency of 95.4% at the load current of 3.5 A.