The Buck-boost converter generates the negative voltage necessary to turn off the direct-drive GaN FET. While it is controlled internally, it requires an external power inductor and output capacitor. The converter is designed to use a 10 µH inductor and a 1 µF output capacitor. As the peak current of the buck-boost is limited to less than 350 mA, the inductor chosen must have a saturation current above 350 mA. A TDK Corporation VLS201610HBX-100M-1 10 µH SMT inductor in a 0806 package is recommended. This inductor is connected between the BBSW pin and ground. A 1 µF, 25 V rated 0603 bypass capacitor is required between VNEG and ground. Due to the voltage coefficient of X7R capacitors, a 1 µF capacitor will provide the required minimum 0.45 µF capacitance when operating.