EE Times Under The Hood - October 8, 2007 - (Page 30) under the hood: MOBILE tests and dust-resistance tests consistent with MIL-STD-810F. We didn’t verify the claims, but a read of the spec certainly bolsters the notion that the tests are a decent proxy for the abuse an average user might heap on a cell phone. The G’zOne offers a modern feature set. A 2-megapixel camera with LED flash joins up with two displays: a 262,144-color, QVGA, 240 x 320pixel, TFT-LCD unit inside, and a monochrome, 100 x 100-pixel, STN display outside. The G’zOne also supports Verizon’s Vcast application suite and video service, along with Assisted GPS (A-GPS) location technology, picture and ringer ID, 72 polyphonic ringtones, 1xEvDO data, an Openwave microbrowser, messaging, predictive text entry and Binary Runtime Environment for Wireless applications. Casio claims the 3.7volt, 1,050-milliampere-hour battery delivers up to 3.2 hours of talk time and 400 hours of standby time. The dual-band CDMA (850/1,900MHz) communications capability relies on a Qualcomm chip set centered on the company’s MSM6550 baseband. The two-chip package splits analog and digital baseband duties into separate dice whose process technologies can be optimized for their respective functions. The radio transceiver path is also split up, this time into separately packaged chips. Given the always-on www.eetimes.com • www.techonline.com Matsushita/Panasonic AN32110A power management ASIC over Qualcomm’s PM6650 alternative. Using underfill for the larger chips’ BGA packages helps with shock resistance. Moving out to the toughened-up enclosure design, the most visible addition is a bumper-car-style fender at the phone’s end. Elsewhere, any button, electrical interface, latch or audio transducer represents a point for incursion of moisture and grime, and it is in those areas that the G’zOne Type-V has focused most on special design features. The machined battery door latch is a spinning catch, so that an O-ring seal can be employed in the feedthrough for the latch mechanicals. An O-ring seal holds up well in a rotating-axle pass-through; the design closely parallels that of the function buttons found on waterresistant watches and chronographs. Similarly, a static O-ring serves as the seal for the headset/charging jack cover, which snaps into place, keeping electrical internals safe. A large gasket is found between the mating surfaces of the upper flip’s two enclosure halves, made of plastic and metal and clamped together in part by machine screw fasteners. In the lower half of the flip enclosure, the keypad mat provides an integral seal. The keypad’s silicone rubber carrier film is oversized to extend all the way to the lower case half’s edge. Elastomer carrier films used for the side keys of the G’zOne are pinched at assembly time to provide seals at the exit point for the other buttons of the enclosure. The electrical cable connecting lower and upper halves relies on a rubber-grommeted feedthrough in the hinge. The polyimide flex cable is water-resistant. Extra hardware for ruggedness comes at a price, with handset weight coming in at 151.5 grams. Overall, it is the G’zOne Type-V’s mechanical design that distinguishes it from an array of alternatives. Whether ruggedness or style is the focus, enclosure design is the most important handset differentiator. ■ IN BRIEF Mobile electronics are often subject to harsh conditions. Because what we carry can often be what we drop, the Casio G’zOne responds with a beefed-up CDMA phone design intended to survive the slings and arrows most of us put our electronics through. Water-proofing, dust-resistance and impact protection are all part of the Casio design. Casio’s heritage in G-Shock watches lets it focus on a tough shell. Component focus nature of CDMA’s frequency-division protocol, Qualcomm thus far has chosen to let the physical isolation of chips address the electrical isolation of potentially interfering signals. On the radio front end, an RFMD RF5144 dual-band RF power amp (transmit) and Qualcomm RFL6000 low-noise amp (receive) join to an interesting “quintplexer” from Avago. The ACFM-7101 combines two duplexers, for isolating the receive and transmit portions of each CDMA band, along with handling signals associated with the G’zOne’s A-GPS function. The internal filters rely on Avago’s film bulk acoustic resonator technology, an alternative to the surface acoustic wave devices in other parts of the G’zOne’s radio implementation. Casio opted for a Qualcomm’s chipset leads the G’zOne value chain, but frequency management remains an opportunity. Surface acoustic wave parts from Epcos and Sanyo provide filters that cannot be integrated into silicon, for cost and performance reasons. From the RF headwaters of the antenna, a film bulk acoustic resonator “quintplexer” from Avago isolates receive and transmit sub-bands in the phone’s two primary bands along with GPS signal isolation.Additional frequency control comes from a Kyocera VCTCXO oscillator having precise temperature-compensating circuits to ensure a 19.2-MHz reference frequency independent of temperature. More noise concerns from the high data rate display interface dictate passive arrays for limiting edge speeds and spurious noise around the connector for the flex joining the main board to the LCD. For a fuller parts list, view this article online at www.techonline.com/underthehood and search article ID: 200001704 30 Electronic Engineering Times, TechOnline | October 8, 2007 http://www.eetimes.com http://www.techonline.com http://www.techonline.com/product/underthehood/200001704
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