US Patent 7944310 Active balun circuit

An active balun circuit is provided, which includes an input end, a first and a second output ends, a first and a second transistors, a feedback capacitor, and a current source. The input end receives an input signal. A drain of the first transistor is coupled to the second output end, and a gate of the first transistor is coupled to the input end. A gate of the second transistor is coupled to a ground end, and a drain of the second transistor is coupled to the first output end. The feedback capacitor is coupled between the second output end and the gate of the second transistor. One end of the current source is coupled to sources of the first and second transistors, and the other end of the current source is coupled to the ground end.