Single-package integration of RF blocks for a 5 GHz WLAN application

Transceivers for future digital telecommunications applications (third gene ration cellular, wireless LAN) need to be portable (compact), battery-power ed and wireless. Today's single-chip solutions for RE front-ends do not yie ld complete system integration. For example, they typically still need exte rnal components for impedance matching, for antenna switches, for power amp lifiers and for RF bandpass filters (BPFs). Furthermore, problems of substr ate coupling (either manifesting as analog crosstalk or as noise coupling f rom the digital part to the analog part on mixed-signal chip) become more i mportant with increasing integration. A system-in-a-package (SiP) approach can address these problems. High quali ty components can be integrated in the package, avoiding lower quality on-c hip passives or circumventing expensive chip technology adaptations. Virtua lly all external components can be integrated, as shown in this paper for t he case of the bandpass filters and the impedance matching. Even the antenn a is a candidate for integration in the package. Further, a clever chip par titioning can reduce the substrate coupling problem. Partitioning also allo ws using the best IC-technology for each component. This paper reports on a fully integrated single-package RF prototype module for a 5 GHz WLAN receiver front-end, which is intended to demonstrate the concept of SiP integration. The approach, that is illustrated here with pro totype RF blocks for a 5 GHz WLAN application, is implemented with a thin f ilm multichip module (MCM-D) interconnect technology. This technology also allows the integration of high quality passive components. With these passi ves, low-loss filters can be implemented. The use of passives, filters and off-the-shelf, active, bare die components opens the way to successful syst em integration.