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NEC GPS chipset targets mobile apps

Posted: 15 Jul 2003 ?? ?Print Version ?Bookmark and Share

Keywords:upd77534? nec electronics? arm7 tdmi-based system lsi? upb1009? rf/if down converter chip?

The uPD77534 device from NEC Electronics Corp. is an ARM7 TDMI-based System LSI for signal processing that is fabricated on 0.15?m process. As a chipset solution with the uPD77534, the company has also developed the uPB1009 RF/IF down converter chip which is connected to the signal processor device and converts the high frequency Global Positioning System (GPS) satellite signal to a low frequency signal used to establish location.

Designed to enhance GPS functions for cellphones and other mobile applications, the chipsets enable correspondence in three modes - Mobile Station (MS)-assisted mode, MS-based mode, and autonomous mode.

The MS-based mode decreases the amount of calculation at the handset by utilizing the data that the servers in the network called Serving Mobile Location Center (SMLC) download from GPS satellites and by having the servers operate the final calculation for positioning. However, while realizing highly accurate positioning even inside or between buildings, this method requires transmission cost in exchanging data between the terminal and the server.

To pursue inexpensive optimal positioning, the MS-assisted mode and autonomous mode have been added in the uPD77534. In the MS-based mode, the mobile handset receives assistant data from the server but does the final position calculation itself. In the autonomous mode, all the calculations are done in the handset side and data from the server is not required. By flexibly shifting the mode from one to another according to the situation, cost-effective GPS function can be achieved in mobile applications.

The total power consumed in location mode is below 61mA, reduced by 40 percent from the existing chipset. In operating mode, the power consumption of the uPD77534 and uPB1009 are 34mA and 27mA, respectively.

The uPB1009 is packaged in 44-pin QFN and is priced at $3, while the uPD77534 is offered in 161-pin TFPBGA and is priced at $8.50, both for 500,000-unit quantities.

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