February 05, 2007
Nokia's E61 provides a bigger, brighter screen and more connectivity options than the Q and BlackBerry 8700c.
Nokia, Motorola Field QWERTY-Friendly Handhelds
Taking full advantage of the 70-mm product width, the E61 packs a 71-mm-diagonal TFT QVGA display backlit by six LEDs and able to show images in 24-bit Truecolor. High-bandwidth connectivity options include W-CDMA, Bluetooth and Wi-Fi. The unit packs a discrete applications processor, Texas Instruments Inc.'s Omap 1710.
The E61's communications processor--separate from the applications processor--is stacked with a Samsung NOR and double-data-rate SDRAM in a package-on-package configuration. The PoP comes as something of a surprise, given the amount of green space on the E61's pc board. But we suspect Nokia is proving out the PoP configuration in a low-volume, high-margin product for implementation in future high-volume, lower-margin products.
The cellular radio of the E61 also uses package-level complexity to reduce component placements and simplify board-level assembly. A single BGA package houses a transceiver IC combined with seven bulk acoustic wave (BAW) filters on a glass substrate to implement WCDMA and GSM protocols across four bands, hiding complexity and again reducing board-level part footprints. Similarly, the Wi-Fi found in the Nokia E61 is provided by a three-dice package from STMicroelectronics combining the Wi-Fi transceiver, power management and baseband/MAC.
A big, bright screen, discrete applications processor and multiple radios require big batteries, and that is exactly what is found in the E61. At 1,500 milliampere-hours and a cell energy density of 542 milliwatt-hours/cc, the lithium polymer battery in the E61 is one of the most capable batteries examined in a cell phone, and accordingly one of the more costly, adding an estimated $2 to the bill of materials when compared with those found in the Motorola Q and the RIM BlackBerry 8700c.
Staying on task: RIM 8700c
RIM pares costs with an integrated applications processor and digital baseband from Marvell, the PXA901. The baseband not only provides the digital processing for all cellular communications--quad-band GSM, GPRS and Edge--but also serves as the engine for the suite of applications delivered by the BlackBerry OS. Our recent column on the Blackberry Pearl (www.eetimes.com, search article ID: 196901128) provides additional details on the PXA90x processor in a die photograph.
The PXA901 does not save on costs through reductions in the baseband and application processor silicon area, since the 112 mm2 of the PXA901 is larger than the combined digital baseband and application processor area found in the Nokia E61. Instead, the savings are realized by eliminating a memory subsystem.
Whereas the Q and E61 require two memory subsystems (one for the digital baseband and one for the apps processor), the PXA901 requires only a single 32-Mbyte NOR memory from Intel Corp. and a 16-Mbyte mobile SDRAM from Elpida Memory Inc. The PXA901, NOR memory and SDRAM are all stacked in one BGA package using a flex substrate. An additional 32-Mbyte NOR from Intel provides user storage.
Thanks for the memories
The path to a mobile e-mail machine can vary depending on the targeted markets, deployed features, desired costs and selected component suppliers. E-mail machines with lower costs, smaller form factors and additional features should roll this year.
Jeff Brown is a principal analyst at Portelligent (Austin, Texas). The company produces teardown reports and related industry research on wireless, mobile and personal electronics (www.teardown.com).
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