25 YEARS: Chip revolution at heart of handset progress

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Crucial trends in the semiconductors that drive mobile-phone functionality have enabled much of the progress in handset form and function.
Miniaturization is among those trends.
“When the cellular industry began, chips’ ‘geometries’ were barely below 1 micron in size and now all we’re shipping is either 90 nanometers or 65 nanometers,” said Will Strauss, principal at Forward Concepts, a semiconductor research firm. “And everybody is heading for 45 nanometers next.”
(A nanometer equals one-billionth of a meter, which is about 39 inches. In cellphone chips, nanometer sizes refer to the width of lines etched in silicon that collectively act as transistors. Each reduction in size – say, from 65 nanometers to 45 nanometers – means doubling the number of transistors on the same size silicon. Performance goes up, cost goes down.)
“With the reduction in size, wonderful things happen,” Strauss said. “First, power consumption goes down, which means longer battery life. Second, processing speed can rise. This reduction in ‘geometries’ means we can cram more transistors onto the same size piece of silicon. That mirrors Moore’s Law, which predicted the doubling of transistors on an integrated circuit every 18 months.”
Mobile telephony’s reliance on digital signals led to DSP chips, or digital signal processors. Lone DSPs have given way to SoCs, or systems-on-a-chip, with a DSP core surrounded by memory, peripherals and application processors, Strauss said.
“It’s a continuing trend towards integration to a single ‘Big Mama’ chip,” Strauss said. “We’re already there at the low-end, but not in the smartphone category – yet.”
Chip trends also enable more features. Bluetooth, Wi-Fi and GPS integration into the handset, for instance, could not have happened economically at chips’ larger, earlier geometries, which proved too costly to add these functions. With smaller geometries, adding these features is no longer cost-prohibitive, the analyst pointed out.
Finally, the advent of 3G network speeds has brought mobile broadband.
“If you’re going to surf the Web, 3G is what you want to enjoy enriched graphics and higher bandwidth,” Strauss said.
The next technical hurdle, according to Strauss: 45nm chips are coming next year, which will provide yet greater functionality on the same amount of silicon, providing the means to handle 4G mobile technologies at speeds greater than the DSL landlines of today.