Patent 7420423 was granted and assigned to Electronics and Telecommunications Research Institute on September, 2008 by the United States Patent and Trademark Office.
An active balun device is provided. The active balun device includes: a differential input portion for receiving an external single input signal to output two complementary differential signals; and a differential amplifier connected to the differential input portion in cascade to amplify the two differential signals received from the differential input portion. Thus, the active balun device has a sufficient gain and a desired bandwidth in a semiconductor circuit.