Perhaps the 2003 edition of the International Technology Roadmap for Semiconductors (ITRS) sums up the system-on-chip design challenge well: SoC design "is characterized by heavy reuse of intellectual property (IP) to improve design productivity, and by system integration that potentially encompasses heterogeneous technologies."
It is the second part of the sentence that is the subject of this In Focus report: the challenges of bringing memories and analog/mixed-signal (AMS) functions onto a predominantly digital design.
Because digital design and process technologies are so different from those optimized for analog and memory, designers must compromise-and be fully aware of what those compromises entail. For example, even though the ITRS projects that memory bits may account for an estimated 90 percent of the transistors on SoCs by 2010, bringing embedded DRAM or flash modules onto an SoC process requires essential trade-offs.
Can the lithography correction tools be tweaked to improve memory density while maintaining the signal integrity and power constraints of the digital blocks? Will new types of memory evolve that are well-suited for the marriage with digital? The Virtual Socket Interface Alliance is developing standards for integrating memory blocks from different IP vendors. And the major EDA vendors are developing tools that allow the co-design and co-simulation of the analog and digital blocks.
Chip makers are scaling new heights, embracing mind-boggling design challenges. Texas Instruments Inc. is promising to bring the RF function together with the baseband processor by the end of next year-an ambitious undertaking that promises to affect the cost and power consumption of cell phone chip sets. Indeed, it is likely that almost all high-volume designs will move to single-chip solutions.
One author here addresses the challenges of keeping track of progress among designers who are geographically disparate. That brings to mind worries about designs being outsourced to low-cost nations. But engineers-wherever they live-who learn to integrate digital functions with AMS and memories will never be