Nikkei Electronics Asia -- February 2007
Industry & Market
SiRF India Packs More Functions onto Standalone GPS Chips

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Jan 30, 2007 19:34 Nikkei Electronics Asia
As location-based services take off in the cellular industry, US-based SiRF Technology, which focuses on standalone GPS chips for consumer applications, is working to pack other mobile functions onto its GPS silicon. After developing a single-chip Bluetooth-GPS package with the company's US and Swedish R&D centers, SiRF's India centers at Noida and Bangalore are looking at multi-functional radio (GPS, Bluetooth and Wi-Fi) as the next target on the silicon roadmap, with results expected possibly in 2007, according to Ashutosh Pande, MD, SiRF Technology India (the company's largest R&D hub outside the US).

Packing more functions onto its GPS chip allows SiRF to cope with competitors' moves to migrate GPS functions onto mobile baseband, or to use software-based GPS rather than a standalone GPS chip.

GPS Implementations
Pande added that SiRF has its own software-based GPS implementation, acquired when it bought Enuvis - a San Fransisco-based soft GPS firm. The implementation deploys an RF chip coupled with application processors such as Intel's XScale or TI's OMAP. "This would be useful for devices with infrequent GPS usage - such as for emergency calls. GPS hardware implementations are still optimal for functions such as dynamic location navigation and car multimedia systems."

One advantage of SiRF's CMOS+RF approach is the optimized die size; competitors' products employing more expansive BiCMOS result in a larger die size, as "You cannot optimize your die size with RF and baseband on one die."    

SiRF's clients can choose between several licensing approaches: a standalone chipset, a design directly into the target silicon through licensing arrangements, or even an arrangement where the GPS chip shares gates with other device components to enable filter and memory sharing. Multifunction radio chips are yet another option for OEMs.

Onboard GPS-Bluetooth
With Nokia predicting that half of all mobile phones will have onboard GPS within three-and-a-half years, SiRF is using its global design resources to penetrate this market. SiRF India used advanced low-power techniques to design the GPS-Bluetooth chip using RF expertise from SiRF Sweden (formerly Kisel Microelectronics). The chip comes in a 7 x 10 x 1.2mm MCM package containing RF, baseband and Flash, using a Wipro-enhanced Bluetooth baseband core.

"An intricate power scheme has been implemented between the RF and baseband chips, controlled by an ARM7 processor. The baseband chip does extensive clock gating at multiple core voltage-domains, controlled by on-chip power-switches. Existing EDA tools do not fully support these low-power techniques, so the team used other ways to simulate and verify these power domains, ensuring proper isolation between them. Verification of the power-scheme at the MCM level was another challenge, as a number of analog and RF functionalities need to be modeled.
    
by Jude Pinto