As notebook PCs and digital video products grow faster than the desktop market, consumers are demanding higher capacity with longer reliability and battery life for accessing and storing their digital content. Perpendicular recording technology is the key technique for increasing storage capacity.
Transitions to 90-nm for mixed-signal designs don't deliver the power saving historically achieved using process technology shrinks, requiring silicon providers to leverage their IP. Agere's new channel technology is one of the industry's lowest-power route to improving capacity, reliability and energy efficiency in mass-market disk drives.
Agere's TrueStore RC7200 is a read-channel device that encodes and decodes data. It is the essential component for ensuring the accuracy of all data read from or written to a drive's platter. The read-channel is the heart of custom storage SoCs combining a hard disk controller, serial interface, and memory.
"Read-channels are mixed-signal devicesthey have a strong digital and analog component. When you change geometries, it benefits the digital component," said Duncan Furness, senior read channel product manager, storage division. As geometries decrease, capacitance levels are proportional. That translates into a reduction in operating power, he explained.
"The difficulty is with the analog component of the channel that is not affected by the geometry shrink. As you go to smaller geometries, you pay a penalty in leakage power," Furness said. Leakage current affects battery life in handheld products.
To address leakage current, the read channel runs at a higher-than-normal core voltage. "The designer can more thoroughly turn off the transistors, so you can exceed the threshold voltage," he said.
The TrueStore RC7200 read-channel device offers a 70% reduction in power from Agere's previous-generation, 130-nm device; 15% is accomplished through the process shrink and 55% through IP improvements, he said. Agere also claims that it offers 50% lower power than competing products.
Power optimizations don't impede the signal-to-noise ratio performance, he added. The RC7200 offers up to a 0.5-dB signal-to-noise ratio advantage over competing products, translating to nearly 10% more capacity or higher yields at equivalent capacities.
"Agere has an advantage in that our read-channels have been shown by our [hard disk drive] customers to have an extra half dB improvement in signal to noise ratio, which can translate into an increase in capacity or it can translate into improving yields on the hard drives yields translate into lower-cost products. The ballpark for capacity increase with our channel will account for 10% of the growth or can be used for taking cost out of the product," Furness said.
Agere's TrueStore RC7200 supports perpendicular recording technology that is designed to align bits vertically so that they can be packed more densely to more easily boost a hard disk drive's capacity.
It also supports a dynamic range of clock speeds from 100-MHz to 2-GHz data rates. As a result, the RC7200 can address 84% of the disk drive market. It is scalable across 3.5- and 2.5-inch PC, consumer and enterprise drive segments.
"We also see that the next-capacity point coming up for 3.5-inch drives is 240 gigabytes per platter, and this chip enables that transition from 160-gigabytes to 240. What we also see going on is this transition from desktops to notebooks and the low-power aspects of this channel also enabled this transition as well," Furness said.
Power levels change by frequency. When the RC7200 operates at a speed of 1.5-GHz, for example, it dissipates less than 1-Watt of power, he said. The channel can accommodate power-optimized 2.5-V analog/1.0-Volt digital drive configuration and also supports 3.3/1.2-V legacy designs.
Agere has RC7200 design wins with two of the top three hard disk drive manufacturers. Customers are now sampling fully functional silicon. Pricing for SoC designs using RC7200 is between $8 and $10 in sample quantities.
Agere Systems, 1-800-372-2447, www.agere.com