Texas Instruments Incorporated
Balun With Improved Common Mode Rejection Ratio

Abstract:

A balun includes a first winding which has a first terminal coupled to an input, and a second terminal coupled to a reference potential terminal. The balun includes a second winding magnetically coupled to the first winding. The second winding has a first terminal coupled to a first differential output, a second terminal coupled to a second differential output, and a tap coupled to the reference potential terminal. The balun includes a first parasitic capacitor which has a first terminal coupled to the first winding and a second terminal coupled to the second winding. The balun includes a third winding which has a first terminal coupled to the reference potential terminal and a floating second terminal. The balun includes a second parasitic capacitor which has a first terminal coupled to the third winding and a second terminal coupled to the second winding.