The teardown experts at iFixit have just taken Apple’s new Audio Adapter for iPhone 7 apart, hoping to find out why the Cupertino tech giant really axed the iPhone’s built-in headphone jack and simply put an adapter in the box. While the adapter retails for just $9 in the Apple store, you’d probably think it doesn’t have any complex technology inside. On the contrary though, there’s actually a lot going on in there.
As expected, one end is a simple female 3.5 mm headphone jack, and the other end is a male Lightning connector. But what’s all that silicon around the Lightning connector end? Most of the retail space near the connector is taken up by a single mystery IC. The mystery IC by the Lightning connector is marked 338S00140 A0SM1624 TW— which doesn’t tell us much, other than it’s an Apple part number.
While the official purpose of this IC is unknown, at minimum we can guess that it contains a digital-to-analog converter (DAC) and amplifier, and its counterpart, an analog-to-digital-converter (ADC).
In previous iPhones, both DAC and ADC functions were handled internally. The analog inputs and outputs from the headphone jack were wrangled by a single chip on the logic board, a custom Apple IC labeled 338S00105. The experts say that although the the sound quality does measure a bit worse from the adapter than we might be accustomed to, the difference is virtually unnoticeable by a common ear.
Looks like Apple’s engineers did their job quite well, making this tiny adapter perform much better than most people even thought was possible.