Application hints

LIS331AL

12/16

4

Application hints

Figure 3.

LIS331AL electrical connection

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

filters is in this case:

k

Ω, the equation for the external filter cut-off frequency may be simplified as follows:

The tolerance of the internal resistor can vary typically of

k

Ω; thus the cut-off frequency will vary accordingly. A minimum capacitance of 2.5 nF for

Table 6.

Cut-off frequency

Capacitor value

1 Hz

5

µF

10 Hz

0.5

µF

20 Hz

250nF

50 Hz

100nF

Pin 1 indicator

Vdd

GND

GND

100nF

10

GND

(Top view)

Direction of the

detectable

accelerations

Y

1

X

Z

Digital signals

LIS331AL

(top view)

ST

1

5

13

Cload y

Vout x

Cload x

Optional

Vout y

Cload z

Vout z

2

3

4

12

11

10

9

16

15 14

6

7

8

PD

f

t

1

2

π R

out

C

z

,,

()

⋅⋅

-------------------------------------------------------------------------

=

f

t

5

µF

C

z

,,

()

--------------------------------------- Hz

[]

=