LPS25HB Datasheet, PDF (13/40 Pages) STMicroelectronics – MEMS pressure sensor: 260-1260 hPa absolute digital output barometer

LPS25HB
3
Functionality
Functionality
The LPS25HB is a high resolution, digital output pressure sensor packaged in an HLGA full-
mold package. The complete device includes a sensing element based on a piezoresistive
Wheatstone bridge approach, and an IC interface which communicates a digital signal from
the sensing element to the application.
3.1
Sensing element
An ST proprietary process is used to obtain a silicon membrane for MEMS pressure
sensors. When pressure is applied, the membrane deflection induces an imbalance in the
Wheatstone bridge piezoresistances whose output signal is converted by the IC interface.
3.2
I²C interface
The complete measurement chain is composed of a low-noise amplifier which converts the
resistance unbalance of the MEMS sensors (pressure and temperature) into an analog
voltage using an analog-to-digital converter.
The pressure and temperature data may be accessed through an I²C/SPI interface thus
making the device particularly suitable for direct interfacing with a microcontroller.
The LPS25HB features a Data-Ready signal which indicates when a new set of measured
pressure and temperature data are available, thus simplifying data synchronization in the
digital system that uses the device.
3.3
Factory calibration
The IC interface is factory calibrated at three temperatures and two pressures for sensitivity
and accuracy.
The trimming values are stored inside the device in a non-volatile structure. When the
device is turned on, the trimming parameters are downloaded into the registers to be
employed during normal operation which allows the device to be used without requiring any
further calibration.
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