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Bosch Sensortec | HSMI BME280
3. Moisture sensitivity level and soldering
3.1. MSL and device storage
The BME280 is classified as MSL 1 (moisture sensitivity level) according to IPC/JEDEC standards J-
STD-020C and J-STD-033A.
The device can be soldered Pb-free with a peak temperature of 260°C for 20 to 40 sec. The minimum
height of the solder after reflow shall be at least 50µm. This is required for a good mechanical decoupling
between sensor device and the printed circuit board (PCB).
Note: When designing the solder paste silk print opening window, avoid excess solder paste to allow
good reflow.
To ensure good solder-ability, the devices shall be stored at room temperature (20°C).
The soldering process can lead to an offset shift. The physical origin of this shift is not material aging but
mechanical hysteresis frozen in by the soldering temperature cycle.
Manual unsoldering can lead to further offset shift, especially if the soldering temperature and / or
soldering time is above the given values of 260°C and 40 sec.
Avoid contact of the device with liquids.
3.2. Multiple reflow soldering cycles
The BME280 can withstand in total up to 3 reflow soldering cycles.
This could be a situation where a PCB is mounted with devices from both sides (i.e. 2 reflow cycles
necessary) and where in the next step an additional re-work cycle could be required (1 reflow).
The specified solder drift is valid for up to 3 reflow cycles. Please see the datasheet for more details.
Document number BST-BME280-HS006-00 | May 2018
© Bosch Sensortec GmbH reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such as copying and passing on to third
parties. BOSCH and the symbol are registered trademarks of Robert Bosch GmbH, Germany.
Note: Specifications within this document are subject to change without notice.
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