SAN JOSE, Calif. — Apple continues to use a mix of Qualcomm and Intel cellular baseband processors in the iPhone X. Teardowns of the handsets also show that the company employed a combination of new and old tricks to pack features into its new flagship smartphone.
The iPhone X is the most expensive handset that Apple has produced to date. The company is said to have supply chain problems ramping the new model, but Apple has so far declined to comment.
Reports have emerged that Apple has started designing Qualcomm baseband processors out of handsets for its next generation. If true, the effort could parallel Apple’s gradual shift from using Samsung’s chip foundry to dual-sourcing chips from TSMC and Samsung and now moving completely to TSMC.
Apple packed two substrate-like PCBs into the handset, according to a teardown by TechInsights of a model with an Intel baseband. The high-density substrates use conductors and microvias measuring 10 to 15 um in width to link the two boards. The technique helps keep the handset to a 7.7-mm thickness.
A teardown by iFixit of a model with a Qualcomm baseband described the boards as two halves folded and soldered together and “the first double-stacked board we’ve seen in an iPhone since the very first iPhone.”
The PCB sandwich had 135% of the logic board size of the iPhone 8 Plus, iFixit estimated.
“The density of connectors and components is unprecedented,” it said. “Ounce for ounce, even an Apple Watch has more bare board … the downside of this clever design is that board-level repair will be extremely difficult — near impossible in some cases.”
In all its previous teardowns of smartphones and other products, TechInsights has not seen what it called the substrate-level PCB approach Apple used in the iPhone X. “Experts were expecting [to see this board technique] next year in the Galaxy S9,” said Daniel Yang, a senior analyst at TechInsights.
E. Jan Vardaman, a packaging specialist with TechSearch International, said she was expecting to see some novel board techniques in the iPhone X. She said she would be surprised if the techniques contributed to delays ramping the handset. “Board designs are usually done early on,” she said.
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Microvias along the edge form a PCB sandwich of two logic boards in the iPhone X. Click to enlarge. (All images: iFixit)