SAN JOSE, Calif. — In a recent interview, the chief executive of Maxim Integrated revealed the company is working on a new sub 100 nm analog process for products it will ship next year. Intrigued by the news, I called up Texas Instruments, the world's largest maker of analog chips, to wade deeper into the murky waters of analog process technology.
"There's no Moore's Law for analog, road maps are based on collaborative discussions with customers," said Venu Menon, vice president of analog process development at TI.
Digital processes are marching steadily toward etching their on/off transistors in ever finer lines, creating cheaper, faster chips. But finer lines don't typicaly benefit analog circuits that need to capture and manipulate a broad range of more nuanced signals, Menon said.
TI currently supports about 78 different process technologies, more than 20 of them inherited with its 2011 acquisition of National Semiconductor. "It's a whole different world in logistical complexity," he said.
Today, TI makes analog chips in everything from 500 nm to 65 nm analog and mixed-signal processes in its dozen or so major fabs, Menon said. It uses some 45 nm mixed-signal processes from outside foundries, too, but 250 nm is about the sweet spot.
"The vast majority of products don't need anywhere close to 100 nm for analog," he said.
Rather than finer line pitches, analog chip makers differentiate their processes by a variety of performance and power traits, said Sami Kiriaki, senior vice president of power management at TI. Some processes aim to support 600-700 volts, some aim to support a wide array of voltage breakdowns, some focus on converter frequency levels, and some on capacitor or resistor performance characteristics, he said.
It's always about what the application needs. For instance, electric vehicles have unique needs to handle their many stacked battery cells, he said. At the opposite end of the spectrum, energy harvesting devices for sensor nodes need ultra-low leakage transistors and capacitors tuned to reduce the amount of operating current.
Drivers for LED lights, wireless power charging mats, millimeter wave radar transceivers, and other analog parts have their own sets of requirements.
"It's hard for an analog foundry to customize parts as much as is needed -- foundries want to run a few processes with high volume to make money," Kiriaki said, explaining why the biggest analog companies have their own fabs. "In our business, diversification is a competitive advantage."