Chipworks

Inside we see a very large battery, a camera module, some shielding, and the antenna (which is actually the perimeter of the case).

First, we see a much smaller overall area than products of the previous generation. Chips appear more densely populated and we expect some consolidation into SoCs. We also see the A4 processor (more on that later).Additionally we can see:

• Skyworks SKY77541 GSM/GRPS Front End Module
• Skyworks SKY77542 Tx–Rx iPAC™ FEM for Dual-Band GSM/GPRS

The most obvious device is the Intel marked, 36My1EE. This is a Numonyx Nor and mobile DDR. Next to it is what looks like an Apple white-labeled Infineon transceiver chip. The rest of the interesting bits appear to be covered up.

Here we see the touchscreen controller with die markings 343S0499. This is the same one seen in the iTouch and Magic Mouse.Other devices:

• Samsung K9PFG08 flash memory
• The Cirrus Logic 338S0589 audio codec (Apple branded)
• The AKM8975 – newest magnetic sensor that promises to improve performance over the prior generation
• The Texas Instruments 343S0499 Touch Screen Controller

As expected, Texas Instruments has won the touch screen controller socket with an unbranded chip marked 343S0499. Apple has followed a fairly predictable evolution in the use of touch screen controllers. The first generation of hand held products from Apple used a five-chip solution, the next generations used a three-chip solution, and this generation uses an all-in-one chip from TI. This device should have die markings for Texas Instruments (F761586C) and be a 3 x 3 mm die, with circuitry going across six metal layers. The device functions by measuring the changes in an electrical charge on the touch screen (in a grid-array), hence, the logic on the chip is able to discern what type of multi-touch or gesture is happening. The way in which the screen itself functions is well documented.In order to have such a powerful chip you need both the analog circuitry to drive the grids on the screen and the digital logic to quickly interpret them. This chip features close to 50% digital circuitry in the form of logic and memory, in a 90 nm process technology. The industry follows a roadmap of what is referred to as process technology generations. This 90 nm technology generation was introduced in 2004, but many devices are still made with this geometry today. Of course, the processes have been subject to continuous innovation and improvement (more on the scale of a nm later).

Although we have yet to completely tear down the image sensor module (coming very shortly), industry sources tell us that the 5 MP camera is another win for OmniVision. Apple already disclosed that the sensor used backside illumination (BSI) technology and a 1.75 µm pixel. We will of course confirm that once the device gets out of the teardown lab and into the chip reverse engineering lab. Chipworks has reported on a smaller-pixel 1.4 µm BSI device from OmniVision (shown at left) and we expect some similarities between the devices.OmniVision is one of the few players to have a proven successful implementation of a state-of-the art BSI process. This technology helps to maximize the ability of each pixel to collect light and deliver improved quality in a smaller sized camera. However, to focus only on the BSI would be to under sell the innovation that goes into this CMOS image sensor.The image sensor market is one of the most hotly contested markets, with over 20 players competing for multiple applications. This competition has resulted in significant innovation in a CMOS-based technology, that only a few years ago was the poor sister of CCD technology. Therefore, these devices are not only interesting on a competitive basis, but are great demonstrators of semiconductor innovation. For instance, what does it mean to fit five million little pixels into a die area roughly the size of a pea?It means putting in the circuitry necessary to get the signal from the sensor array, the lens for focusing the light, the color filter, the photo cathode to collect the light, and the isolation to avoid electrical noise into 5,000,000, 1.75µm diameter pixels.

If you are interested in more details on OmniVision’s technology, then you can visit our report library to learn about our full reverse engineering reports.

Microelectromechanical systems (MEMS) are used to sense the motion of the device. It is another red hot sector in the semiconductor industry fuelled by their relatively recent inclusion in consumer portable electronics.Based on industry sources, we believe that the AGD1 part is the new three axis gyroscope designed for Apple by STMicroelectronics. These markings don’t link it to the commercial version, known as the L3G4200D, and it is another piece of silicon that we will be going inside of to show the die images.The other sensor is the STMicroelectronics STM331DLH three-axis accelerometer.By combining the two sensor types the iPhone provides a level of sensitivity and accuracy to translate pretty much any motion into an electrical signal. We can’t wait for the “iPitch” app which will allow budding young baseball pitchers to measure the forces on their curve balls by whipping their iPhones toward home plate.

As expected, Broadcom won the slot for multiband low power 802.11a/b/g/n with Bluetooth. This amazing little chip combines several proven wireless technologies with a CMOS PA, while consuming very little power, due in part to being made in a 65-nm process. Interestingly, it includes an FM radio – something Apple has not yet taken advantage of.In addition to this chip, Broadcom has also scored a win for the BCM4750 single chip GPS receiver IC, fabricated at 90 nm RFCMOS.

The news much of the world is waiting for is whether Apple has released yet another new microprocessor. It turns out that the A4, first seen in the iPad, is used again (as expected) in the iPhone 4. Date codes show it to be a newer ‘batch’ but the device remains the same, with the exception that there is double the memory. This is a package-on-package, and inside we should see a 4 Gb (512 MB) SDRAM die and the processor. Later analysis will show us whether it is one or two SDRAM dies.Since Apple does not manufacture its own silicon, we assume that they have continued to outsource the fabrication of this design to Samsung, who are using a very advanced 45 nm technology. Until we get it back to our reverse engineering lab, we cannot be 100% certain either way. However, we have not heard about any dual-foundry strategy employed by Apple so it is a fairly safe bet to affirm our original assumption.This chip represents the glamorous part of semiconductor technology – the smallest of the small. To understand how technology generations/shrinks are classified you need to be a semiconductor process junkie. Suffice to say, that only a few companies in the world have the R&D, manufacturing, and volume needed to manufacture products at these very small sizes.But what does this mean? Well, basically a transistor is logic that amplifies or switches electronic signals. An integrated circuit contains millions and millions of these. Samsung’s 45 nm process was observed fully in a Xilinx Spartan 6 FPGA reverse engineering analysis we did, which showed a gate length of 47 nm with a full transistor width of about 200 nm. If we were to say that the average a human hair is about 100 µm in diameter (100,000 nm), then that would mean that you can fit over 2000 of these gates across it.

The accelerometer and gyroscopes are both design wins for STMicroelectronics. We have taken a closer look at each of them.The 33DH has been identified by Chipworks as the STMicroelectronics LIS331DLH, based on the package markings. Chipworks has seen this part in an iPad.The AGD1 appears to be essentially identical to the STMicroelectronics L3G4200D 3-axis gyroscope, based on the markings on the MEMS and ASIC dies.

To get such a compact device, the ASIC is stacked above the MEMS structure. The MEMS structure is carefully protected in a bonded silicon lid. Cracking off the silicon lid (requiring considerable skill), we can expose the MEMS device. The top structure is the Z-axis sensor, and the bottom structure contains the X and Y sensors.This is the ASIC die used to process the tiny capacitive signals, and create a standard SPI/I²C digital interface, and several smart features such as click and double-click recognition, wake-up, and motion detection.

This device is a new device, and is the first 4 mm x 4 mm 3-axis gyroscope we have seen from STMicroelectronics. It features an integrated single silicon 3-axis sensor. Previous 3-axis gyroscopes, such as the LYPR540AH, contained two separate silicon sensor dies. The device appears to be essentially the same as the 3-axis L3G4200D low power digital pitch, roll, and yaw gyroscope. The L3G4200D comes packaged in a 4 mm x 4 mm x 1 mm LGA package. It is likely that the AGD1 die markings are specific to the Apple iPhone. It is manufactured using the same THELMA process that is used for the LIS331DH accelerometer.  

The L3G4200D operates as a vibrational gyroscope to sense rotation of the device.

The first of the two microphones inside the iPhone is the Knowles S1950 – found in the phone.Knowles describes its MEMS microphones as being built with a patented CMOS/MEMS technology platform that continues to support high performance and high density innovation in portable electronic devices. The new design variables include smaller sizes, lower profiles and mounting options, increased output capacities, and new digital audio options that eliminate analog noise. For manufacturers, surface mount designs eliminate off-line subassembly production costs.Integrating the circuitry with the microphone lowers the BOM costs and simplifies manufacturing.

When looking at the MEMS die, you get a feeling of how they function. The microphone itself has a quite simple design, comprising two parallel polysilicon plates separated by a small air gap. The upper plate (poly 2) is perforated with an array of small holes (which are needed for the MEMS release etch). A solid poly 1 plate forms the bottom capacitor plate

The second design win for Knowles is the microphone located in the headset included with the iPhone 4. It is interesting to note that the two microphones have different package markings but share identical ASIC and MEMS die markings. The physical features of the locations are different, so packaging is likely a simple matter of fitting the device to the intended application.

Infineon gets the design win for the second of the two microphones in the handset. Infineon is a relatively new entrant into the MEMS market (which until about a year ago was dominated by “startup” companies).Without going into a long explanation, the industry has undergone a lot of change recently, as MEMS have gone mass market. New large device manufacturers have entered MEMS microphones and Akustica, one of the original startups, has been acquired by Bosch.

The die photo for the ASIC doesn’t reveal too much about its functional layout, but we have done a full analysis on a similar device from Infineon (report list below). It could be for RF shielding, or simply to stop folks looking at the die circuitry now that teardowns are getting popular. Of course, that wouldn’t deter us – taking off metal layers is our bread and butter!

This die has a similar membrane structure to the Knowles device, with a very nice artistic job done on the die markings, but they had a lot of space to work with. I suppose it is the nature of the (round) beast to have a lot of wasted silicon, in an industry where shrinking a die by mere percentage points can mean the difference between profit and loss.