A quasi-balun circuit for receiving an unbalanced input and providing signals to a balanced-input low noise amplifier (LNA) is provided. Notably, this quasi-balun circuit can provide a phase difference between the positive and the negative terminals of the LNA that is greater than 90 degrees, but less than 180 degrees. In one embodiment, the quasi-balun circuit can provide a phase difference of approximately 135 degrees. To provide this functionality, the quasi-balun circuit includes a passive, reactive network coupled between the unbalanced input and the LNA.
1. A quasi-balun circuit for receiving an unbalanced input and providing signals to a balanced-input low noise amplifier (LNA), the quasi-balun circuit consisting of:
a capacitor connected between a node and the unbalanced input; and
an inductor having a first terminal connected to a first input terminal of the LNA and a second terminal connected to the node,
wherein the node is connected to a second input terminal of the LNA,
wherein the quasi-balun circuit provides a phase difference between a first input terminal of the LNA and a second terminal of the LNA that is less than 180 degrees.
2. A quasi-balun circuit for receiving an unbalanced input and providing signals to a balanced-input low noise amplifier (LNA), the quasi-balun circuit consisting of:
a first capacitor connected between a node and the unbalanced input;
and
an inductor having a first terminal connected to the first input terminal of the LNA and a second terminal connected to the node,
wherein the node is connected to the second input terminal of the LNA.