Patent ID: 8493126

Claim:
An apparatus comprising: a mixer having a first output lead and a second output lead, wherein the mixer is configured to generate a differential signal based on a first In-phase (I) differential signal and a first Quadrature phase (Q) differential signal received from a local oscillator; and a balun responsive to the differential signal, the balun comprising: a primary winding having a first terminal coupled to the first output lead of the mixer and a second terminal coupled to the second output lead of the mixer; a first capacitor coupled in parallel with the primary winding; a first secondary winding; a second capacitor selectively couplable in parallel with the first secondary winding; a second secondary winding; a third capacitor coupled in parallel with the second secondary winding; and a switch configured to selectively couple a first terminal of the first secondary winding to a first terminal of the second capacitor.