Jim Lipman
EDAnet Site Director
TechOnline

Shrinking silicon technology, better design tools, and the development of silicon-core reuse methodologies have led to multimillion gate SoC designs that fuel today's consumer, computer, and communications systems. What defines a system-on-a-chip, however, has changed since the term first was used in the 1980s.

The first SoCs were large amounts of digital logic on a silicon chip. This logic consisted of megacells, functional blocks of pre-designed and pre-verified circuitry, linked together with glue logic, application-specific logic that served to connect the blocks. Driven by a need for ever-increasing complexity, SoC designers then added memory blocks, processor cores, and DSP engines.

Improving mixed-signal design tools and techniques added analog circuitry to the previously all-digital SoC, reflecting the reality of real-world systems being comprised of both analog and digital elements. In addition, improved process technology put RF circuitry in the mix, very desirable for many wireless communication systems. As technology has helped redefine SoCs, a common thread has linked each generation—every SoC has been strictly an electronic system.

It's time to realize true SoCs—systems that benefit from different types of engineering disciplines or domains. A simple extension of real-world systems having both digital and analog attributes tells us that such systems encompass more than just electronic elements. Multidomain SoCs are not just concepts waiting to be realized—they're here now in some very essential technological arenas.

One example is biotechnology, where lab-on-a-chip designs are just starting to reach the marketplace. Both established and emerging companies are combining electronic circuitry, microelectromechanical systems (MEMS), and optical subsystems to make complete chemical and other complex analysis systems on a silicon chip.

Because of the variety of available MEMS components, MEMS-enhanced SoCs are particularly interesting. Included in MEMS-implemented components are microfluidic chip-based subsystems for chemical and biological applications, optical structures for communication systems, micromirror arrays for microdisplays and optical steering, and various sensors for parameters such as pressure and motion.

The engineering barriers to multidomain SoC-based systems are formidable but not insurmountable. These obstacles include cost-effective process development, a need for unique chip packaging technology, and new design tools that effectively integrate multidomain design analysis and verification. Although some design tools for multidomain design already exist, they are inadequate for developing chips of SoC complexity that contain diverse electronic, fluidic, mechanical, and optical subsystems.

Engineers thrive on technology advancements that enhance their own skills. Yesterday's digital hardware designers have morphed into today's SoC designers. Along the way, these designers have supplemented their digital-hardware expertise with embedded-software knowledge and analog design skills. Tomorrow's SoC designer may very well also have optical, fluidic, and mechanical design proficiency for designing the next portable blood-analysis instrument or extraterrestrial atmospheric probe.