2 Mechanical and Electrical Specifications

LIS2L02AQ3

8/17

CD00059664

Self Test allows to test the mechanical and electrical part of the sensor. By applying a digital

signal to the ST input pin an internal reference is switched to a certain area of the sensor and

creates a defined deflection of the moveable structure. The sensor will generate a defined

signal and the interface chip will perform the signal conditioning. If the output signal changes

with the specified amplitude than the sensor is working properly and the parameters of the

interface chip are within the defined specifications.

Output impedance describes the resistor inside the output stage of each channel. This

resistor is part of a filter consisting of an external capacitor of at least 320pF and the internal

resistor. Due to the high resistor level only small, inexpensive external capacitors are needed to

generate low corner frequencies. When interfacing with an ADC it is important to use high input

impedance input circuitries to avoid measurement errors. Note that the minimum load

capacitance forms a corner frequency beyond the resonance frequency of the sensor. For a flat

frequency response a corner frequency well below the resonance frequency is recommended.

In general the smallest possible bandwidth for an particular application should be chosen to get

the best results.