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by tyingq 2788 days ago
"Any clues why such an environment doesn't make Android phones behave in such a way?"

A bit of googling seems to indicate most smart phones have a crystal oscillator. But, Android would have the advantage of manufacturer diversity...so lots of different types of crystal oscillators, perhaps some that are sealed better than the iphone ones, or quartz vs silicon, etc.

This does sort of illustrate an issue with the iphone tech monoculture. Lots of devices with similar components, and similar versions of software. Find something that adversely affects them, and you can disrupt a lot of people. It's probably hard to find something similar for Android since the hardware and even software varies a lot.
1 comments
alxlaz 2788 days ago
Most crystals have better sealing :-). SiTime explicitly(-ish) acknowledges that their older-generation packaging was less efficient on their website:

"How effective is the hermetic seal of MEMS oscillators??

One of the key elements enabling extremely stable MEMS resonators is SiTime’s EpiSeal™ process which hermetically seals the resonators during wafer processing, eliminating any need for hermetically sealed ceramic packaging. SiTime’s EpiSeal resonator is impervious to the highest concentration elements in the atmosphere, nitrogen and oxygen, and therefore acts as a perfect seal. Previous generations of EpiSeal resonators may have been impacted by large concentrations of small-molecule gas. Newer EpiSeal resonators are impervious to all small-molecule gases. Please contact SiTime in case you are planning to use a SiTime device in large concentrations of small-molecule gas, so that we can recommend an appropriate, immune part."

https://www.sitime.com/support/faqs

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NormM 2787 days ago
Apple uses these oscillators. They are substantially more expensive than crystal oscillators, but are much smaller and use less power. This may explain why the Android phones, which are more price sensitive, didn't use them. It does seem that the current generation of SiTime oscillators don't have a problem with Helium, so perhaps current generation iPhones don't either.
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