LIS3L02DQ

6/19

3.2 IC Interface

The complete measurement chain is composed by a low-noise capacitive amplifier which converts into an

analog voltage the capacitive unbalancing of the MEMS sensor and by three

Σ∆ analog-to-digital convert-

ers, one for each axis, that translates the produced signal into a digital bitstream.

The

Σ∆ converters are tigthly coupled with dedicated reconstruction filters which removes the high fre-

quency components of the quantization noise and provides low rate and high resolution digital words.

The charge amplifier and the

Σ∆ converters are operated respectively at 107.5 KHz and 35.8 KHz.

The data rate at the output of the reconstruction depends on the user selected Decimation Factor (DF)

and span from 280 Hz to 4.48 KHz.

suitable for direct interfacing with a microcontroller.

The LIS3L02DQ features a Data-Ready signal (DRY) which indicated when a new set of measured accel-

eration data is available thus simplifying data synchronization in digital system employing the device itself.

The LIS3L02DQ may also be configured to generate an inertial wake-up/interrupt signal when a program-

mable acceleration threshold is exceeded along one of the three axis.

3.3 Factory calibration

The IC interface is factory calibrated to provide to the final user a device ready to operate. The parameters

which are trimmed are: gain, offset, common mode and internal clock frequency.

The trimming values are stored inside the device by a non volatile structure. Any time the device is turned

on, the trimming parameters are downloaded into the registers to be employed during the normal opera-

tion thus allowing the final user to employ the device without any need for further calibration.

4

DIGITAL INTERFACES

terfaces. The latter may be SW configured to operate either in SPI mode or in 3-wire interface mode.

tied high (i.e connected to Vdd).

Table 5. Serial Interface Pin Description

PIN Name

PIN Description

CS

SPI enable

SCL/SPC

SPI Serial Port Clock (SPC)

SDA/SDI/SDO

SPI Serial Data Input (SDI)

3-wire Interface Serial Data Output (SDO)

SDO

SPI Serial Data Output (SDO)