LPS25HB to LPS25H Temperature Difference

[Matthias Schranz]

Posted on December 18, 2017 at 14:24

We are currently replacing the LPS331AP in our design. we favour the the LPS25HB. i'm working with the STEVAL-MKI165V1 Kit, which is directly connected to our board.

 The pressure seems to be in a reasonable range but the temperature readings are really off.

The LSP25HB measures a temperature of only 18.06�C while the old LPS331AP measures 23.53�C and the LSP25H measures 22.8�C.

The datasheet states a accuracy of +/- 2�C. Which is true for LPS25H, but the LPS25HB is 6 �C off.

I found no difference in software (referring to the datasheet) between LPS25HB and LPS25H regarding initialization or conversation.

Why is there such a big temperature difference? The temperature measurement is quite important for us, and we do not have the space to put an extra temperature sensor on the board.

We even bought a second evaluationkit of the LPS25HB to verify our measurements. and they are both too low.

Thank you for your help!

#lps25hb #lps25h

[Miroslav BATEK]

Posted on December 20, 2017 at 15:01

The temperature sensor in these pressure sensors is primarily used for temperature compensation of the pressure sensor itself and is not optimized on temperature accuracy. In datasheet is written only typical value but the maximum inaccuracy can be higher, even 6°C is possible. And it can vary for each piece. You would have to calibrate each device.

You can consider to use LSP22HB which has better accuracy.

Unfortunately I can't share min/max accuracy of the temperature sensor publicly on this forum, but you can try to send a request to

http://www.st.com/content/st_com/en/support/online-support.html

. The request will be evaluated based on your business case.