January 21, 2010 -- SOCs (systems-on-chips) have historically represented the Holy Grail for electronics because using these chips allows electronic systems designers to pack a lot of digital circuitry into a small area. Nevertheless, fine-line CMOS does not suit use in analog, power, and RF functions, and tiny CMOS transistors are prone to noise and leakage problems. Further, the dedicated mask set you need to make the chip can cost more than $1 million. You then must commit to that design until high-volume sales amortize its costs. For these reasons, it sometimes makes more sense to use separate chips rather than pack everything onto one.

Dave Robertson, vice president of analog technology at Analog Devices, advocates employing "smart partitioning" rather than dictating a dogma for either integration or "disintegration"—that is, moving functions onto other chips. "You have to look at each case and pick the smart thing to do," he says. "The smart thing to do in 2010 was not the same smart thing to do in 2007 and may not be the same smart thing to do in 2013."

By Paul Rako, EDN Technical Editor