ug505UG505: Si8239x-EVB User's Guide The Si8239x isolated gate drivers are ideal for driving power switches used in a wide va-riety of power supply, inverter, and motor control applications,SKYWORKS UG505: Si8239x-EVB Isolated Gate Driver Evaluation Kit. UG505: Si8239x-EVB User's Guide. The Si8239x isolated gate drivers are ideal for driving power switches used in a wide variety of power supply, inverter, and motor