At the bottom left corner of the overview photo, you'll see a 2-megapixel Micron CMOS sensor, which combines with a three-element, fixed-focus, fixed-focal-length lens to create the iPhone's flash-deficient and still-image capture-only camera.
The 3.7V lithium-ion battery in the bottom right corner of the photo consumes a dominant percentage of the iPhone's total volume, and is a key determinant of the device's substantial specified battery life. Apple estimates that after 400 recharge cycles, the battery will still retain up to 80% of its original caPACity; replacing it will cost you $79 plus $6.95 shipPINg, with an estimated three-business-day turnaround. For an additional fee, the company will even loan you a spare iPhone while yours is in the shop.
Between the iPhone's camera and battery, in the photo, you'll find a single flex circuit that encompasses all of the iPhone's antennas; a combined 2.4-GHz Bluetooth/Wi-Fi element and a separate (and much larger) multiband (850-, 900-, 1800- and 1900-MHz) cellular element. The planar antennas attach to the phone speaker's acoustical chamber.
The 3.5-in. diagonal (2×3-in.) LTPS TFT LCD (Picture), which includes National Semiconductor's Mobile Pixel Link serial interface receiver in a Chip-on-glass implementation, delivers a 480×320-pixel (half-VGA) resolution at 160 dpi, but Apple doesn't specify the display's color depth (either native or dithered). The touchscreen elements arrange in a coordinate system capable of supporting both self- and mutual-capacitance modes, thereby enabling simultaneous multitouch support managed by an Apple-labeled, Broadcom-supplied touchscreen controller and an NXP Semiconductor ARM 7TDMI processor. The "How Stuff Works" site has a good summary of how the iPhone's touchscreen works its magic.
The main board assembly, swathed in EMI-shiELDing material, is a two-PCB (digital and RF) sandwICh, which you CAN see between the camera module and antenna in the overview photo. Note that in the images that follow, the background grid dimension is 1 cm. One side of the digital board is dominated by a 4- or 8-Gbyte NAND flash Chip (depending on the iPhone model), on the PCB's left side. If you visit Samsung's website, the largest device you'll find listed there is a 32-Gbit (4-Gbyte) NAND flash memory, and only single bit-per-cell devices are represented. While Samsung could get to 8 Gbytes in a single PACkage by implementing a two-die arrangement, I've long suspected (and other teardowns have confirmed) that Apple is an early customer for S amsung's nascent MLC (multilevel-cell, aka two-bit-per-cell) NAND-flash-memory program. This is the same NAND flash memory used in the iPod nano.
The other dominant IC on that same side of the digital PCB is an Apple-labeLED applications processor on the right, with a volatile memory underneath it in a two-package stack. Die-level analysis by Portelligent and Semiconductor Insights has confirmed that the applications processor is a Samsung design, thereby following in the footsteps of Samsung's first CPU design win with Apple in the second-generation iPod nano. A specific part number is unknown at this time; the IC may not (yet?) be available in the open market. However, hackers' analysis of the iPhone's recovery firmware has uncovered some interesting CPU specifications:
* ARM 1176JZF with TrustZone, believed to be running at upwards of 600 MHz
* ARM Intelligent Energy Manager
* 16-kbyte/16-kbyte code/data cache
* Vector floating point coprocessor
* ARM Jazelle-enabled for embedded-Java execution
* SIMD high performance integer CPU with an eight-stage pipeline, capable of 675 Dhrystones/sec and 2.1 MIPS
* 0.45 mW/MHz power draw (with cache).
Firmware decoding also points to the Samsung CPU's inclusion of an Imagination Technologies-licensed graphics core, which if true would be quite ironic given my conversation with a company representative during January's Consumer EleCTRonics Show.
What about that "volatile memory" I mentioned? It's a source of dISAgreement between Semiconductor Insights and Portelligent. Semiconductor Insight's video claims that the chip is an SRAM, but Portelligent is adamant that its die inspection identifies the device as a mobile (that is, low-power) DDR SDRAM.
Asked about this memory device and another I'll discuss a bit later, Don Stroud, Portelligent's director of business development, said, "We have reviewed both of the memory chips in question and still believe our assessments are correct….We did a detailed review of the package marking and then extracted the die from their respective packages to get the die markings. So, package and die markings, coupled with data sheets, make us very confident of our assessments. It would be interesting to pose the same questions to others who have analyzed the iPhone, and to know what manner of verification they employed to derive their conclusions." Translation: Touché, Semiconductor Insights!
I haven't seen the die plot myself, so I can't say for sure what memory technology's inside, but the cost-per-bit advantage of DRAM over SRAM is indisputable. And given the greater-than-50% gross profit margin that Apple's reportedly aCCruing, controlling bill-of-materials costs is obviously critical to the company. With that said, you can't overlook DRAM's higher average power consumption than SRAM, due to the need for perioDIC refresh, although low power-tuned SRAMs tend not to have significantly faster access times (random or sequential) than their DRAM peers. A feature article published nearly four years ago goes into DRAM-versus-SRAM tradeoffs in great detail, and I commend it to your inspection if you want to learn about this topic in greater depth.
In the upper right corner of the NAND flash memory is STMICroeleCTRonics' MEMS-based aCCelerometer IC, used to detect the iPhone 's orientation of the moment (portrait versus landscape) in order to adjust the display. Right now the function is only enabLED for Web browsing, photo viewing, and iPod audio-and-video playback. As I wrote in a recent hands-on analysis, the accelerometer only reliably detects portrait-versus-landscape orientation when a user holds the iPhone at least 45° relative to the ground (and better yet nearly vertical, at ~90° to the horizontal). At the time I did my initial report, I wasn't sure if this quirk represented a fundamental sensor hardware limitation or only a cons traint of the currently shipPINg SOFtware. However, subsequent feedback from one of my anonymous contacts suggests that the former is the case:
When the phone is hELD in front of you (vertically), gravitational forces on the accelerometer's "fingers" allow the phone to understand whether you are holding it in portrait or landscape mode. When you lay the phone on a table or hold it horizontally, gravitational forces operate uniformly around the accelerometer so it has no way of knowing where you are relative to it and CAN't determine whether you are trying to look at a portrait- or landscape-mode orientation.
Mind you, it's not a big deal; I naturally tend to cradle the iPhone cupped in my hand at waist-level, parallel to the ground, among other reasons because it requires less effort than holding the unit vertical in front of my face. In my preferred viewing position, the sensor is ineffective, but I can always temporarily raise the phone to a vertical position before rotating it, and then lower the unit again to its usual position. In fact, one could even paint this attribute as a "feature"—a sort of display-LOCk capability. Regardless, it's something for Apple and its accelerometer partners(s) to look at for the second-generation iPhone design.
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