Recent product launches of the Q from Motorola and the E61 from Nokia illustrate the importance of the pocket-friendly, QWERTY keyboard e-mail phone (e-mail machine) in the product portfolios of cell phone makers. With the success of Research In Motion (RIM) Ltd. and Palm Inc., which have historically focused on integrating voice and e-mail capabilities into a handset with QWERTY keyboard, other leading cell phone makers have followed suit by bringing similar devices to market.
A design comparison of three recent e-mail machine offerings--the Motorola Q, Nokia E61 and RIM BlackBerry 8700c--highlights distinct feature, hardware architecture and component supplier approaches to marrying voice and e-mail capabilities in an ultraportable handheld.
Thin is in--Motorola Q
Borrowing from the success of the ultrathin Razr, the Q from Motorola Inc. set a new benchmark in thinness for an e-mail machine: 14 mm. Motorola strategically depopulated areas of the pc board to allow the nesting of major subassemblies, like the display and battery, against open areas of the board.
Other industrial design techniques Motorola employed to keep the Q on a diet included an EL keypad backlight to avoid LED diffuser thickness; planar antennas, which conform largely to case walls; and placement of the acoustic assembly, camera module and antenna outside other mechanical stackups. Pushing subassemblies to the ends stretches the Motorola Q by 5 mm compared with the 110-mm height of the RIM BlackBerry 8700c.
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At the heart of the Motorola Q, a Marvell Technology Group Ltd. PXA270C5312 provides the applications processing, while a Qualcomm Inc. MSM6500 two-dice analog baseband/ digital baseband package enables cdma2000 1xEV-DO communications. The two-chip architecture, provides design flexibility but incurs a board space and cost penalty, with each processor occupying a unique socket and requiring a separate memory subsystem.
Nokia's E61 provides a bigger, brighter screen and more connectivity options than the Q and BlackBerry 8700c.
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
Keeping the bells and whistles to a minimum while delivering on the required functions of worldwide cellular voice and anytime, anywhere e-mail, the RIM BlackBerry 8700c is put together at an estimated, best-in-class hardware BOM just north of $110.
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
A benefit of the NOR-based architecture employed by RIM is the amount of memory available to the user for storing e-mail, contacts and calendar events. Of the 64 Mbytes of flash on board, the BlackBerry 8700c provides the user with 50 Mbytes, or 78 percent. At the other end of the spectrum, the Motorola Q provides only 42 Mbytes of user memory, despite a combined 160 Mbytes of on board flash. The heavier OS and application suite from Microsoft Corp. found in the Q contributes to the low amount of user-available memory.
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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