A balun includes an unbalanced port having a single-ended terminal, a balanced port having first and second differential terminals, and first and second series resonant LC circuits. The first series resonant LC circuit is connected between the first and second differential terminals, and includes a first element of a first type and one element of a second type connected in series. The second series resonant LC circuit is connected between the single-ended terminal and ground, and includes second and third elements of the first type and the one element of the second type connected in series. The one element of the second type is shared by the first and second series resonant LC circuits. The first differential terminal is connected between the one element of the second type and the third element of the first type.