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Application hints LIS2L02AL
10/17
4 Application hints
Figure 3. LIS2L02AL Electrical connection
Power supply decoupling capacitors (100nF ceramic or polyester + 10µF Aluminum) should
be placed as near as possible to the device (common design practice).
The LIS2L02AL allows to band limit Voutx and Vouty through the use of external capacitors.
The re-commended frequency range spans from DC up to 2.0KHz. In particular, capacitors
must be added at output pins to implement low-pass filtering for antialiasing and noise
reduction. The equation for the cut-off frequency (f
t
) of the external filters is:
Taking in account that the internal filtering resistor (R
out
) has a nominal value equal to
110kΩ, the equation for the external filter cut-off frequency may be simplified as follows:
The tolerance of the internal resistor can vary typically of
±20% within its nominal value of
110kΩ; thus the cut-off frequency will vary accordingly. A minimum capacitance of 1nF for
C
load
(x, y) is required in any case.
.
Table 5. Filter capacitor selection, C
load
(x,y)
Cut-off frequency Capacitor value
1 Hz 1500 nF
10 Hz 150 nF
20 Hz 68 nF
50 Hz 30 nF
100 Hz 15 nF
200 Hz 6.8 nF
500 Hz 3 nF
Vout X
100nF
Cload x
LIS2L02AL
10µF
Vdd
Vout Y
GND GND
Cload y
(top view)
Optional
Optional
Digital signals
DIRECTION OF THE
DETECTABLE
ACCELERATIONS
1
Y
X
GND
ST
f
t
1
2π R
out
C
load
xy,()
⋅⋅
--------------------------------------------------------------=
f
t
1.45µF
C
load
xy,()
-------------------------------Hz[]=
