Apple

One of Apple's key semiconductor engineers has left the company, even as the iPhone giant tries to take more control over what goes inside its devices.

Gerard Williams III, senior director in platform architecture, departed Apple last month after nine years, according to a person familiar with the matter.

While not well known outside of Apple, Williams led development of every Apple processor core from the A7 -- the first 64-bit processor for mobile devices -- to the A12X, the chip powering Apple's latest iPad Pro devices. Apple says its newest chip makes its iPads faster than 92 percent of the world's computers.

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In recent years, Williams' responsibilities had grown beyond leading the design of the custom CPU cores for Apple's chips to overseeing the layout of the various parts of the system-on-a-chip, or SoC, inside the company's mobile devices. It's standard for chip designers to pack more and more features -- like the CPU brains of the device, GPU graphics and memory -- onto the same physical package to improve battery life and reduce the size of the chips. In the case of Qualcomm, its Snapdragon processors also integrate its wireless modem onto the SoC.

Williams' departure comes as Apple ramps up its efforts to create more of its components and as it hires more engineers around the globe. Apple has been designing its own chips since the early days of the iPhone. In 2010, it introduced its first Apple-branded chip, the A4, for the iPad it sold that year. Every year since then, it has released new A-series processors that power its mobile devices, and Apple's even expected to design its own chips for Mac computers as early as next year. The strategy stands in contrast to many Android phone makers, who rely on processors made by Qualcomm.

Williams' departure is a loss for Apple. His work likely will show up in future Apple processors, and he's listed as an inventor on more than 60 Apple patents. Some relate to power management, memory compression and multicore processor technology.

Apple declined to comment.

Apple's chip push

Apple's decision to design its own chips has given it more control over its devices, as well as differentiated itself from rivals. While it has created the brains for its iPhones and iPads for years, it lately has made moves to design even more of its components on its own. That has included the Bluetooth chip that pairs its AirPods to an iPhone, as well as the security chips that save your fingerprint and other key data. Apple is reportedly working on its own graphics processors, modems and power management chips.

Some features of Apple's A-series chips, spearheaded by Williams, have led the industry and have caused rivals to respond.

After Apple introduced the A7 64-bit processor for its mobile devices in late 2013, Qualcomm's customers put pressure on the company to do the same, as Qualcomm testified during January's antitrust trial against the US Federal Trade Commission. Qualcomm wasn't prepared for 64 bit and scrambled to tweak its processor. The resulting chip didn't perform well and didn't take off with customers, which hurt Qualcomm's position in the market.

Williams isn't the first notable Apple engineer to leave its chip business, which is led by Johny Srouji. Two years ago, Apple SoC architect Manu Gulati left for a similar role at Google. After Gulati left Apple, Williams took over his role overseeing SoC architecture.

Before joining Apple in 2010, Williams for 12 years worked at Arm, the company whose designs are used in virtually all mobile processors. He hasn't yet joined another company.