Apple Watch's major components

Teardown: Apple Watch

Apple makes every square inch of real estate in the Watch do a job.

From a design perspective, the Apple Watch sets new benchmarks for what can be squeezed into a wearable product. However, it does so at the expense of non-recurring engineering costs that even the sharpest analysts are struggling to fathom.The design story has two parts. The first is about the various features and components that Apple has fitted into a physical package that is either 38.6×33.3×10.5mm or 42×35.9?×10.5mm. The second is about the S1 system-in-package (SiP) that drives the device and how much silicon and functionality Apple has integrated there alongside the new APL0778 applications processor.

The pictures tell more of the story than usual here because size matters. For example, iFixit has partnered with Creative Electron to take x-ray images of the Watch as well as carrying out a traditional teardown. The most interesting shows the Watch next to one of the earliest sports/GPS wristwatches, a 2012 vintage Nike+ Sports GPS.

“The Apple Watch is far more densely packaged, with virtually no extra space, and sports a very noticeable inductive charging coil. The Nike features (comparatively) giant screws, spacious chip mapping, and sensors that spill out beyond the central watch body,” notes iFixit.

You need to add that while the Watch Sport will be the bestselling model - the cheapest in an expensive range at £249 ex VAT - Apple has squeezed a lot more into its entire Watch range than Nike did (or could) three years ago.
The Watch can be used for phone calls, messaging, social media, email and to control a number of iPhone tasks. Other apps are being added daily.

Then there are the physical features. The Watch has more on-board sensors. There is the Digital Crown that provides device navigation. There is the Taptic Engine that provides haptic feedback.

Apple has achieved much by using the smallest viable components. The battery is rated at 205mAh for 18 hours of general-purpose use (though much reduced for audio playback or talk time). The battery in the Samsung Gear Live is rated at 300mAh and so is much bigger.

Many components have been artfully tucked into various parts of the body. iFixit found the antenna in a tiny recess at the top, while the microphone ribbon cable had been wrapped between the inner and outer layers of the case.

All these shrinks do not make the Watch easy to repair - though poking around any complex timepiece has never been recommended. But the biggest obstacle to any tinkering is the S1: it is fully encased with all peripheral cables soldered to the reverse.

This has not stopped reverse engineering specialists at Chipworks from going inside the SiP and finding a treasure trove of components. Its discoveries tell the second part of the design story.

“Inside the S1 SiP alone we have catalogued more than 30 components. Now, some of those components contain multiple die; the package-on-package (PoP) assembly, for example, contains the new Apple processor and the DRAM die. The NFC [near-field communication] solution also contains the secure element as well as the NXP NFC controller and radio,” says Chipworks. “So there are 30 individual components, and at least 30 pieces of silicon, all in a package that is only 26×28mm.”

The apps processor measures 5.2×6.2mm and is manufactured on Samsung’s 28nm process. Chipworks expects this will get even smaller with a move to the incoming 14nm process.

The inevitable pressures on device and SiP real estate also appear to have led Apple away from some usual suppliers of key components.

“At the top left corner of the S1 module we were expecting to see a motion sensor from InvenSense, but, surprise surprise, we have a brand new STMicroelectronics 3×3mm land grid array (LGA) package featuring a 3D digital gyroscope and accelerometer,” says Chipworks. Particularly significant for that design win is that the InvenSense sensors had worked with an external rather than internal accelerometer.

Then, a further envelope-pushing decision has been to use smaller but more expensive chip-?scale packages for the S1 rather than soldered components.

But all the Watch’s innovation - physical and electronic - carries a cost. Just how much of a non-recurring engineering burden has the Watch involved? That kind of analysis has always been difficult with Apple, but has become even more so as the firm has moved to developing its own silicon for consumer products. In that regard, the S1 alone is an especially complex item.

The two main cost analysts are at odds. IHS says the unit production cost (excluding software and marketing) is $83.70; TechInsights says $138.40. That’s already a big difference, but now a third ‘informed’ player has joined the fun.

Until last December, Hristo Daniel Ushev was director of market and competitive intelligence for Motorola Mobility’s strategy team, covering the period when it launched the Moto 360 smartwatch. On his website, Mobile Forward, Ushev suggests that the IHS call could be out by at least 2× - that would take things to almost $170 (although he describes the TechInsights estimate as ‘reasonable’).

Ushev argues that the estimates do not fully recognise the level of innovation required for products in this very new market space and the resulting likelihood that manufacturing will suffer very low yields, at least initially. He also notes the presence of dedicated chips and use of highly customised metal-?working for the Watch body.

But even Ushev acknowledges that really nobody knows anything, apart from Apple itself. And Cupertino isn’t talking.

Apple has set a new design standard, but bear in mind that wearable tech remains an expensive game. Also, while we might have ignored the elephant for a few hundred words, just how desirable the Watch proves to consumers is the only thing that really matters.

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