STEVAL-MKI021V1 STMicroelectronics, STEVAL-MKI021V1 Datasheet - Page 12

• Manufacturer Part Number: STEVAL-MKI021V1
• Description: BOARD EVALUATION LIS331AL
• Manufacturer: STMicroelectronics
• Series: MEMSr

Specifications of STEVAL-MKI021V1

• Sensor Type: Accelerometer, 3 Axis
• Sensing Range: ±2g
• Interface: Analog
• Sensitivity: 0.145 x Vdd = V/g
• Voltage - Supply: 3 V ~ 3.6 V
• Embedded: No
• Utilized Ic / Part: LIS331AL
• Acceleration: 2 g
• Sensing Axis: Triple Axis
• Output Type: Analog
• Operating Voltage: 18 V
• Operating Current: 6 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-8205

Application hints
4
12/16
Application hints
Figure 3.
Power supply decoupling capacitors (100 nF ceramic or polyester + 10 µF aluminum) should
be placed as near as possible to the device (common design practice).
The LIS331AL allows to band limit Voutx, Vouty and Voutz through the use of external
capacitors. The recommended frequency range spans from DC up to 2.0 kHz. In particular,
capacitors are added at output Voutx, Vouty, Voutz pins to implement low-pass filtering for
antialiasing and noise reduction. The equation for the cut-off frequency (f
filters is in this case:
Taking into account that the internal filtering resistor (R
kΩ , the equation for the external filter cut-off frequency may be simplified as follows:
The tolerance of the internal resistor can vary typically of
kΩ; thus the cut-off frequency will vary accordingly. A minimum capacitance of 2.5 nF for
C
Table 6.
load
PD
ST
(x, y, z) is required.
Digital signals
LIS331AL electrical connection
Filter capacitor selection, C
GND
2
3
4
1
5
Cut-off frequency
16 15 14
LIS331AL
6
(top view)
10 Hz
20 Hz
50 Hz
1 Hz
7
8
100nF
GND
f
t
=
10
13
12
11
9
------------------------------------------------------------------------ -
2π
f
t
Cload y
⋅
Cload z
Cload x
10
GND
=
R
µ
-------------------------------------- - Hz
C
F
out
load
load
⋅
5µF
(x,y,z)
(
C
1
x y z
load
Vdd
,
,
Optional
(
x y z
out
,
)
[
±
) has a nominal value equal to 32
20% within its nominal value of 32
,
]
)
Capacitor value
X
Vout z
Vout x
Vout y
250nF
100nF
0.5µF
5 µF
(Top view)
Direction of the
detectable
accelerations
t
) of the external
1
Pin 1 indicator
LIS331AL
Z
Y