SAN JOSE, Calif. " Cellular phones are poised to take yet another step in silicon integration by packing hard-disk drive controllers and read channels into their baseband processors. At least three companies are at some stage of exploring such designs, though several sources expressed doubts about when and at what pace hard disks will appear in cell phones.
The possibility of hard drives coming to the 500 million unit/year cell phone market is particularly attractive to Agere Systems Inc., which generates a third of its revenue in storage silicon. "We can see a convergence of hard-disk drives and mobile electronics," said Matthew Kendall, a senior product-marketing manager.
The company, which has articulated a vision of personal broadband products to drive that opportunity forward, today will announce a line of read channel chips that includes a hard-disk controller geared for 1-inch and smaller drives. Agere is considering integrating the controller and low-power read channels into its cellular baseband chips as a cost- and space-saving measure for getting the small drives into handsets. In such a design, the only electronics in the drive might be a preamplifier and motor control circuit.
Putting drive electronics in the baseband "is a reasonable thing for Agere to do," said Will Strauss of market watcher Forward Concepts (Tempe, Ariz.). "This won't become a major part of the cell phone market, but it could be a lucrative one."
Separately, 1-inch-drive startup Cornice Inc. has disclosed that its next-generation drives will hand off read-channel processing to a host CPU as part of a simplified design for consumer systems. The drives will appear in several high-end cell phones next year, Cornice said.
Agere is expected to announce in a few weeks a deal with Cornice that may involve its read-channel parts. "We have a relationship with them," confirmed Curt Bruner, chief technology officer of Cornice.
At least one other company is "strongly considering" a cellular baseband chip with integrated drive electronics, Bruner added.
Engineers have some technical concerns about the different frequencies of baseband and storage devices, but the biggest problem is determining whether enough handsets are ready to adopt drives to justify adding the silicon costs to a baseband, Bruner said. At a recent conference on camera phones, Mike Butler, a director of business strategy in Nokia's imaging group, said that disk drives still draw too much power and are too unreliable to be embedded in mainstream cell phones.
"Our feeling is when the first phones come out with embedded hard drives, they will be so compelling that other major providers will quickly follow," said Bruner of Cornice.
"It's pretty clear in the long run [hard drive] support will be required [in handsets]," said Avner Goren, manager of the Omap line of cellular processors at Texas Instruments Inc. However, he said TI is not ready to reveal its plans in this area.
Agere already supplies read-channel parts to 1-inch-drive makers Hitachi Global Storage Technologies and China-based startup GS MagicStor. Its baseband chips are used by Samsung and NEC, said Strauss of Forward Concepts.
The RC1100ULP is Agere's first read-channel device geared for 1-inch and smaller drives. The design is optimized for lowest leakage current so that it consumes minimal power in sleep mode. It offers a 350-MHz data rate geared for the small drives, which generally have a rotation rate or 3,000 rpm or slower.
Agere is pairing the read channel with its first hard-disk controller design. Though most drive makers design their own controllers as part of their proprietary edge, Agere believes many disk companies would rather buy a controller as a merchant chip or core to get more quickly and cheaply into the still-emerging market for 1-inch and smaller consumer drives. Indeed, Seagate and Maxtor are both preparing to enter this market (see April 19, page 1). Agere's Kendall said he expects two interfaces will emerge for drives in cell phones: streamlined versions of ATA for embedded models and CompactFlash II for removable drives.
The consumer read channels are one of four market-specific parts Agere is to announce today that share a common digital back-end architecture. All of them use a new digital finite-impulse-response filter but have analog front ends geared for individual market segments. "This allows us to control costs and gives us a time-to- market advantage," said Kendall.
The high-end RC7100HS read channels are Agere's first server chips designed for system-on-chip integration. Kendall said that the cores would be paired with ARM control processors and drive interface electronics currently implemented in a separate chip.
The server chips sport a data rate up to 2.5 GHz and are made in a 90-nanometer process. All the other read channels are made in 130-nm technology.
The desktop RC6700 read channels have a maximum data rate of 2 GHz. Like the server devices, they can handle 160 Gbytes/platter, aimed at 3.5-inch drives. The 6700LP mobile parts are a derivative of the desktop chips using a higher transistor voltage threshold to lower power consumption 20 percent. They hit data rates up to 1.2 GHz and serve drives with up to 80 Gbytes/platter on 2.5- and 1.8-inch drives.
The server, desktop and mobile parts come in 84-pin MLCC packages when used as discrete chips. The consumer read channels are packaged in 54-pin MLCCs.
All the chips will sample by year's end. The server read channels and integrated chips with the controller and consumer read channels will not ship until next year.