RF/analog and digital faceoff — friends or enemies in an RF SoC

With the ever-increasing functionalities of cellular smart phones and other communication systems, RF circuits at multi-GHz frequencies have recently migrated to the state-of-the-art low-cost digital CMOS processes despite their unfriendly analog design environment. The use of digital techniques to assist RF performance is becoming a common practice. However, there is a general fear that a fully integrated RF SoC containing DSPs could easily fail due to mysterious integration issues such as silicon substrate coupling. In this paper, we will visit some of the practical aspects based on the experiences of integrating the Digital RF Processor (DRP™) in the past ten years. Some conventional wisdom that is actually not wise for RF SoCs will be illustrated. As a result of the successful commercialization of DRPs, CMOS integrated radio SoCs with digitally assisted RF is proven to be one of the clever directions and has opened additional avenues toward software-defined radios.