What is the silicon square on the LPS22HB and LPS25HB?

[mart J]

Posted on June 18, 2018 at 11:17

In section 10.1 of the datasheet for the LPS22HB the square on top of the package is labelled as 'Sensing area (exposed silicon)', which makes it sound quite fragile.  However I noticed in a recent press release:

http://www.st.com/content/st_com/en/about/media-center/press-item.html/t4028.html

 the LPS22HB is listed as 'Dust-free and water-resistant by design'.  Is this square of silicon the sensing element or a protective cap (how fragile is it?), and is that the same of the LPS25HB?

Many thanks.

[Miroslav BATEK]

Posted on June 18, 2018 at 12:02

Yes, the square of silicon is sensing element.

it is not fragile, it is more flexible. 

It is the same as in the LPS25HB.

[mart J]

Posted on June 18, 2018 at 17:42

OK thank you for that information.  Is the sensor dust and water resistant?  I would think any dust on the sensing element will at least affect the readings?

[Miroslav BATEK]

Posted on June 19, 2018 at 16:33

The sensor LPS22HB is water resistant but not waterproof. Common dust should not be a problem, but if you want to use is in some very dusty area if you recommend to put the sensor in a box wit some filters.

If you need waterproof sensor please use LPS33HW or LPS35HW.

[mart J]

Posted on June 19, 2018 at 19:26

Thank you Miroslav.  The environment I want to use this in isn't especially dusty so it sounds like this sensor will be OK for me. 

Thanks again.