While a foldable iPhone posed a new challenge for Apple’s thermal engineering team, they came up with a creative way to use the device’s hinge to their advantage. Here are the details. The iPhone Duo’s hinge features a flexible graphite tube. PCMag recently sat down with Dan Murray, Apple’s vice president of silicon engineering, and Banafsheh Barabadi, the company’s senior manager of thermal product design, to discuss the architecture of the A20 Pro chip. The new SoC, which powers the iPhone 18 Pro, iPhone 18 Pro Max, and iPhone Duo, is Apple’s first iPhone chip built on a 2nm process, following the technology’s debut with the M6 chip in the Mac mini in August. And while the A20 Pro was designed with the three new iPhones in mind, the iPhone Duo version includes some additional capabilities. These include a second display engine to run both displays simultaneously. From PCMag: The A20 Pro variant of the iPhone Duo is slightly different. “For iPhone Duo, we added a second display engine to support simultaneous operation of the internal and external displays,” says Murray, “and with the increased CPU and GPU performance, we ensure that we can deliver a smooth user experience on all displays. For the internal display, we also added support for placing the FaceTime camera behind the screen.” The report offers a really interesting and in-depth look at the A20 Pro’s thermals and the new vapor chamber Apple developed to keep them at bay. That includes what Apple calls “metal on foam,” a material that iFixit also examined during the recent teardown of the iPhone 18 Pro. The second pillar is a new material that bridges the gap between the A20 Pro and the vapor chamber. “We call it metal-on-foam,” says Barabadi, and “it basically creates a direct thermal and mechanical coupling between the SoC and the vapor chamber. It’s very effective at removing heat and meets the strict mechanical requirements of the system. It took us months of development to get the material properties exactly right so we could use this material.” Perhaps the most interesting fact of the story is what Apple did to improve the thermal performance of the iPhone Duo, particularly considering the challenges of dissipating heat in a device that doubles its thickness when folded. From the report: “This was one of the most technically challenging aspects of our design,” says Barabadi. To fix the problem, Apple ran a flexible graphite tube through the hinge to transfer heat between the two halves, thus increasing the surface area available for heat dissipation. “This part needs[ed] which will be designed jointly between our thermal team and the mechanical team. It’s a flexible material that needs to survive, as you can imagine, many hinge cycles while maintaining its thermal connectivity and also its structural integrity throughout the life cycle of the product.” PCMag’s interview with Murray and Barabadi also discusses the architecture of the A20 Pro, including the benefits of placing the DRAM next to the processor rather than stacking it on top, and you can read it in full here. It’s worth checking out on Amazon FTC: We use automatic affiliate links to generate income. More.
