According to a teardown performed by Chipworks, Apple decided to use another provider for its accelerometers.
According to developer RealityCap, the iPhone 5S incorporates an accelerometer manufactured by Bosch Sensortech and not one produced by STMicroelectronics, as was the case with previous iPhone generations.
Choosing this new type of accelerometer manufactured by Bosch wasn’t one of the best decisions taken by Apple as its applications provide incorrect results.
The two types of accelerometers have different specifications and this creates a discrepancy between the information displayed to users.
The site writes that the two accelerometers share similar variance, but their bias specification is contrasting.
“This is where we find the problem: the typical bias for the ST part is +/- 20mg, while the Bosch part lists +/-95mg. This almost 5x greater offset range is confirmed by our measurements, and is absolutely consistent with the failures being reported by users and the media. Specifically, a +/- 20mg offset range would translate to around a +/-1 degree accuracy range in tilt detection, and a +/-95mg offset translates to +/-5 degrees in tilt.”