Design of RF filters using silicon integrated passive components

The paper discusses the design and characterization of RF filters in Freescale´s 0.4 micron SiGe BiCMOS process. An integration scheme for bandpass filters on a standard silicon substrate using monolithic transformers is presented. A 1.9 GHz filter using a single transformer as well as its dual, where the transformer is replaced by three inductors, is fabricated and measured up to 10 GHz. It is demonstrated that the transformer-based filter occupies less chip area than its inductor-based dual, with similar performance. In addition, results of a 1.7 GHz lowpass (harmonic) filter that exclusively uses high-quality factor (Q) inductors and metal-insulator-metal (MIM) capacitors, designed using scalable models is presented. First pass results show very good agreement between models and measurement.