LIS3DSH datasheet(18/53 Pages) STMICROELECTRONICS

18 / 53 page

Mechanical and electrical specifications

LIS3DSH

18/53

Doc ID 022405 Rev 1

When an acceleration is applied to the sensor the proof mass displaces from its nominal

position, causing an imbalance in the capacitive half bridge. This imbalance is measured

using charge integration in response to a voltage pulse applied to the capacitor.

At steady-state the nominal value of the capacitors are a few pF and when an acceleration is

applied, the maximum variation of the capacitive load is in the fF range.

3.8

IC interface

The complete measurement chain is made up of a low-noise capacitive amplifier which

converts the capacitive unbalancing of the MEMS sensor into an analog voltage that is

finally available to the user through an analog-to-digital converter.

The acceleration data may be accessed through an I2C/SPI interface, therefore making the

device particularly suitable for direct interfacing with a microcontroller.

The LIS3DSH features a Data-Ready signal (RDY) which indicates when a new set of

measured acceleration data is available, therefore simplifying data synchronization in the

digital system that uses the device.

3.9

Factory calibration

The IC interface is factory calibrated for sensitivity (So) and Zero-

g level (TyOff).

The trimming values are stored inside the device in a non volatile memory. Any time the

device is turned on, the trimming parameters are downloaded into the registers to be used

during the active operation. This allows to use the device without further calibration.

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