Cost and performance tradeoff analysis in radio and mixed-signal system-on-package design

An optimal total solution for radio and mixed-signal system integration needs tradeoffs between different design options. Among various design metrics, cost and performance are probably the two most important factors for design decisions. In this paper, we review and analyze cost-performance tradeoffs of system-on-chip (SOC) versus system-on-package (SOP) solutions for radio and mixed-signal applications. A new design methodology, which quantitatively predicts performance and cost gains of SOP versus SOC, is presented. The performance model evaluates various mixed-signal isolation techniques between sensitive analog/RF circuits and noisy digital circuits in SOC or SOP. The cost analysis includes new factors such as extra chip area and additional process steps for mixed-signal isolation, seamless integration of "virtual components" or intellectual property (IP) modules, yield and technology compatibility for merging logic, memory and analog/RF circuits on a single chip, and extra costs for moving passives off chip. In addition to these, a complete and systematic analysis method for on-chip versus off-chip passives tradeoffs is presented. The analysis and modeling techniques explore tradeoffs between performance, cost, robustness, and yield when different on-chip or off-chip passives are used. It thus provides a complete picture of quantitative tradeoffs for using on-chip or off-chip passives. The design methodology and analysis techniques are then demonstrated through several design examples in wireless applications. It is clearly shown that for all complex and high performance mixed-signal systems, SOP is a lower cost solution than SOC. Finally, some design guidelines for SOC versus SOP and on-chip versus off-chip are concluded.