The BME280 Handling, Soldering, and Mounting Instructions document mentions that “it is not recommended to place the sensor close to the edge of the PCB”. Is there any more clarification on how close is too close?
There is no specific minimum distance. MEMS devices have tiny mechanical structures inside, the main issue with mounting parts at the very edge of the PCB is when the design is panelized, assembled at the panel level, PCBs are separated by snapping or cutting.
The high mechanical stress that can occur with the sawing of the PCBs can exceed the absolute maximum rating and damage the sensor internal structures. (This is true for all MEMS).
With that in mind, please find a suitable placement for the sensor, taking into account thermal effects from other components, as well as airflow. If the sensor must be placed on the edge of the board, adding a few millimeters of distance can increase your yield, depending on how the PCBs are manufactured.
Is the BME280 lifetime calibrated?
The working lifetime of a sensor is highly dependant on the use-case, environmental and stress conditions, etc. Therefore Bosch cannot guarantee a standard lifetime because there are so many different applications and respective mission profiles our sensors are used for.
Is there calibration certificates available for the BME280?
Bosch does not have extra calibration certificates for their sensors, as the expected performance is already as listed in the specifications of the datasheet.
What measuring principles are used for the BME280?
The specific details are confidential, but the BME280 uses the following measurement principles:
Temperature: diode voltage
All information was provided by Bosch Sensortec’s Forum.