The SC4905A/B is a 10 pin BICMOS primary side voltage mode controller for use in Isolated DC-DC and off-line switching power supplies. It is a highly integrated solution, requiring few external components. The device features a high speed oscillator with integrated feed forward compensation, accurately programmable maximum duty cycle, voltage mode of operation, line voltage monitoring, supply UVLO, low start up current, low voltage current limit threshold and user accessible reference.