Small digital-to-analog converter chips were discovered when Apple’s Lightning EarPods and Lightning-to-3.5mm adapter, both included with the iPhone 7, went through a teardown. though their exact supplier remains a mystery.
The DAC in the EarPods was labeled “338S00140 / A0QK1623 / TW,”. The one in the adapter was marked “338S00140 / A0MU1621 / TW,” The “TW” could be a reference to Taiwan, where a number of Apple suppliers are based according to Vietnamese site Tinhte.
The iPhone 7 is Apple’s first major product to completely abandon a 3.5-millimeter headphone jack in favour of Lightning and Bluetooth audio. Because many people still rely on 3.5-millimeter accessories — an industry standard — Apple bundled the adapter by default, despite the new EarPods and the growing prevalence of Bluetooth headphones and speakers.
Apple’s usual partner on such components, Cirrus Logic, might have been responsible for designing the chips. Certainly they were manufactured by another firm — possibly Taiwan-based TSMC, which also manufactures Apple’s A-series processors. In 2015, Cirrus switched back to TSMC from Vanguard International Semiconductor. Doubts regarding the same have been intensified by discoveries suggesting that a Taiwan-based company is now constituting a large part of Apple’s Supply Chain.