Balun Design for Silicon RF Integrated Circuits

In this paper, we present the design and analysis of an on-chip transformer balun for silicon RFIC. High-performance on-chip transformer baluns for low-noise amplifiers and power amplifiers on multilayer radio-frequency integrated circuits are constructed. Single-end primary and differential secondary are constructed on different dielectric surface planes. The metal windings of the primary and secondary arc in parallel to form coupled lines. Both the primary and the secondary are designed symmetrically for differential operation. Additional layer interfaces and vias are used to provide bridges to assure the geometric symmetry. Examples of designs with test results arc discussed.