Page 1
3-axis ±2 g analog-output ultracompact accelerometer
Features
■ Single voltage supply operation
■ ±2 g full-scale
■ High stability over temperature
■ Ratiometric output voltage
■ Power-down mode
■ Embedded self-test
■ 10000 g high shock survivability
■ ECOPACK
(see Section 7)
®
RoHS and “Green” compliant
LIS332AR
MEMS motion sensor:
LGA-16
circuit which is trimmed to better match the
sensing element characteristics.
(3x3x1.0mm)
Applications
■ Tilting applications
■ Free-fall detection
■ Gaming
■ Anti-theft systems
■ Inertial navigation and motion tracking
Description
The LIS332AR is a miniaturized low-power 3-axis
linear accelerometer belonging to the “nano”
family of ST motion sensors. It includes a sensing
element and an IC interface to provide an analog
signal to the external world.
The sensing element, capable of detecting the
acceleration, is manufactured using a dedicated
process developed by ST to produce motion
sensors and actuators in silicon.
The IC interface is manufactured using a CMOS
process that allows the design of a dedicated
Table 1. Device summary
Order code Temperature range [°C] Package Packing
The LIS332AR has a full-scale of ±2 g, and is
capable of measuring accelerations over a
maximum bandwidth of 2.0 kHz. The device
bandwidth may be reduced by using external
capacitors. The self-test capability allows the user
to check the functioning of the sensor in the final
application.
ST is already in the field with several hundred
million sensors which have received excellent
acceptance from the market in terms of quality,
reliability and performance.
The LIS332AR is provided in a plastic land grid
array (LGA) package.
Several years ago ST successfully pioneered the
use of this package for accelerometers. Today, ST
has the widest manufacturing capability and
strongest expertise in the world for production of
sensors in plastic LGA packages.
LIS332AR -40 to +85 LGA-16 Tray
LIS332ARTR -40 to +85 LGA-16 Tape and reel
February 2010 Doc ID 16931 Rev 1 1/14
www.st.com
14
Page 2
Contents LIS332AR
Contents
1 Block diagram and pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Pin connections and description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Mechanical and electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Mechanical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1 Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2 Zero-g level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.3 Self-test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.4 Output impedance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1 Sensing element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2 IC interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.3 Factory calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Application hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.1 Soldering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.2 Output response vs. orientation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2/14 Doc ID 16931 Rev 1
Page 3
LIS332AR Block diagram and pin description
1 Block diagram and pin description
Figure 1. Block diagram
A
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1.1 Pin connections and description
Figure 2. Pin connection
3(
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2OUTY
2OUTZ
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Doc ID 16931 Rev 1 3/14
Page 4
Block diagram and pin description LIS332AR
Table 2. Pin description
Pin # Pin name Function
1 NC Internally not connected
2 res Connect to Vdd
3 NC Internally not connected
4 ST Self-test (logic 0: normal mode; logic 1: self-test mode)
5 PD Power-down (logic 0: normal mode; logic 1: power-down mode)
6 GND 0 V supply
7 NC Internally not connected
8 NC Internally not connected
9 Voutz Output voltage Z channel
10 NC Internally not connected
11 Vouty Output voltage Y channel
12 NC Internally not connected
13 Voutx Output voltage X channel
14 NC Internally not connected
15 res Connect to Vdd
16 Vdd Power supply
4/14 Doc ID 16931 Rev 1
Page 5
LIS332AR Mechanical and electrical specifications
2 Mechanical and electrical specifications
2.1 Mechanical characteristics
-Vout
(a)
.
(1)
Max. Unit
±2 g
0.2*Vdd
–5%
0.2*Vdd
0.2*Vdd
+ 5%
±2 %
60 700 mV
60 700 mV
60 700 mV
-40 +85 °C
(Vst=logic 0)
LOAD
), with C
LOAD
>2.5 nF
@ Vdd=3 V, T=25 °C unless otherwise noted
Table 3. Mechanical characteristics
Symbol Parameter Test condition Min. Typ.
(4)
(4)
(6),(7)
(2)
Delta from +25 °C ±0.01 %/°C
T=25 °C Vdd/2-6% Vdd/2 Vdd/2+6% V
Delta from +25 °C ±0.2 mg/°C
Best fit straight line ±0.5 % FS
Vdd=3 V 100 µg/
T=25 °C
Vdd=3 V
X axis
T=25 °C
Vdd=3 V
Y axis
T=25 °C
Vdd=3 V
Z axis
All axes 2.0 kHz
(8)
(Vst=logic 1)
=2.0 kHz. Sensor bandwidth=1/(2*π*32kΩ*C
RES
Ar Acceleration range
So Sensitivity
SoDr
Sensitivity change vs.
temperature
(3)
Voff Zero-g level
OffDr
Zero-g level change
vs. temperature
NL Non linearity
CrossAx Cross-axis
Acceleration noise
An
density
Self-test output
Vt
voltage change
Fres
Top
Sensing element
resonant frequency
Operating
temperature range
(5)
Wh Product weight 30 mgram
1. Typical specifications are not guaranteed
2. Guaranteed by wafer level test and measurement of initial offset and sensitivity
3. Zero-g level and sensitivity are ratiometric to supply voltage
4. Guaranteed by design
5. Contribution to the measured output of an inclination/acceleration along any perpendicular axis
6. “Self-test output voltage change” is defined as Vout
7. “Self-test output voltage change” varies cubically with supply voltage
8. Minimum resonance frequency F
V/g
Hz
a. The product is factory calibrated at 3 V. The operational power supply range is specified in Table 4. Since the
device is ratiometric, Voff, So and Vt parameters vary with supply voltage.
Doc ID 16931 Rev 1 5/14
Page 6
Mechanical and electrical specifications LIS332AR
2.2 Electrical characteristics
@ Vdd=3 V, T=25 °C unless otherwise noted
Table 4. Electrical characteristics
Symbol Parameter Test condition Min. Typ.
Vdd Supply voltage 2.16 3 3.6 V
Idd Supply current
Mean value
PD pin connected to GND
(b)
.
(1)
0.3 mA
Max. Unit
IddPdn
Vst
Vpd
Rout
Supply current in
power-down mode
Self-test input
Power-down input
Output impedance of
Voutx, Vout y, Vout z
Capacitive load drive
Cload
fo r Vo u t x , Vo u ty,
(2)
Voutz
Turn-on time
To n
at exit from
power-down mode
To p
1. Typical specifications are not guaranteed
2. Minimum resonance frequency F
Operating
temperature range
=2.0 kHz. Device bandwidth=1/(2*π*32kΩ*C
RES
PD pin connected to Vdd 1 µA
Logic 0 level at Vdd=3 V 0 0.2*Vdd
V
Logic 1 level at Vdd=3 V 0.8*Vdd Vdd
32 kΩ
2.5 nF
C
in µF 160*C
LOAD
+0.3 ms
LOAD
-40 +85 °C
LOAD
), with C
LOAD
>2.5 nF
b. The product is factory calibrated at 3 V.
6/14 Doc ID 16931 Rev 1
Page 7
LIS332AR Absolute maximum ratings
3 Absolute maximum ratings
Stresses above those listed as “Absolute maximum ratings” may cause permanent damage
to the device. This is a stress rating only and functional operation of the device under these
conditions is not implied. Exposure to maximum rating conditions for extended periods may
affect device reliability.
Table 5. Absolute maximum ratings
Symbol Ratings Maximum value Unit
Vdd Supply voltage -0.3 to 6 V
Vin Input voltage on any control pin (PD, ST) -0.3 to Vdd +0.3 V
A
A
T
Acceleration (any axis, powered, Vdd=3 V)
POW
Acceleration (any axis, not powered)
UNP
Storage temperature range -40 to +125 °C
STG
3000 g for 0.5 ms
10000 g for 0.1 ms
3000 g for 0.5 ms
10000 g for 0.1 ms
4 (HBM) kV
ESD Electrostatic discharge protection
Note: Supply voltage on any pin should never exceed 6.0 V.
This is a mechanical shock sensitive device, improper handling can cause permanent
damage to the part
This is an ESD sensitive device, improper handling can cause permanent damage to
the part
1.5 (CDM) kV
200 (MM) V
Doc ID 16931 Rev 1 7/14
Page 8
Terminology LIS332AR
4 Terminology
4.1 Sensitivity
Sensitivity describes the gain of the sensor and can be determined by applying 1 g
acceleration to it. Because the sensor can measure DC accelerations, this can be done
easily by pointing the selected axis towards the ground, noting the output value, rotating the
sensor 180 degrees (pointing towards the sky) and noting the output value again. By doing
so, a ±1 g acceleration is applied to the sensor. Subtracting the larger output value from the
smaller one, and dividing the result by 2, produces the actual sensitivity of the sensor. This
value changes very little over temperature (see sensitivity change vs. temperature) and over
time. The sensitivity tolerance describes the range of sensitivities of a large number of
sensors.
4.2 Zero-g level
Zero-g level describes the actual output signal if there is no acceleration present. A sensor
in a steady state on a horizontal surface will measure 0 g on both the X and Y axes,
whereas the Z axis will measure 1 g. Ideally, the output for a 3 V powered sensor is Vdd/2 =
1500 mV. A deviation from the ideal 0 g level (1500 mV, in this case) is called Zero-g offset.
Offset is to some extent a result of stress to the MEMS sensor and therefore the offset can
slightly change after mounting the sensor onto a printed circuit board or exposing it to
extensive mechanical stress. Offset changes little over temperature (see “Zero-g level
change vs. temperature” in Table 3: Mechanical characteristics). The Zero-g level of an
individual sensor is also very stable over its lifetime. The Zero-g level tolerance describes
the range of Zero-g levels of a group of sensors.
4.3 Self-test
Self-test (ST) allows the checking of sensor functionality without moving it. The self-test
function is off when the ST pin is connected to GND. When the ST pin is tied to Vdd, an
actuation force is applied to the sensor, simulating a definite input acceleration. In this case,
the sensor outputs exhibit a voltage change in their DC levels. When ST is activated, the
device output level is given by the algebraic sum of the signals produced by the acceleration
acting on the sensor and by the electrostatic test-force. If the output signals change within
the amplitude specified in Table 3, then the sensor is working properly and the parameters
of the interface chip are within the defined specifications.
4.4 Output impedance
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 2.5 nF and the internal
resistor. Due to the resistor level, only small inexpensive external capacitors are needed to
8/14 Doc ID 16931 Rev 1
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 close to the resonant frequency of the sensor. In
general, the smallest possible bandwidth for a particular application should be chosen to
obtain the best results.
Page 9
LIS332AR Functionality
5 Functionality
The LIS332AR is a 3-axis ultracompact, low-power, analog output accelerometer packaged
in an LGA package. The complete device includes a sensing element and an IC interface
capable of taking information from the sensing element and providing an analog signal to
the external world.
5.1 Sensing element
A proprietary process is used to create a surface micro-machined accelerometer. The
technology allows the creation of suspended silicon structures which are attached to the
substrate at several points called “anchors” and are free to move in the direction of the
sensed acceleration. To be compatible with traditional packaging techniques, a cap is
placed on top of the sensing element to prevent blocking of the moving parts during the
moulding phase of plastic encapsulation.
When an acceleration is applied to the sensor, the proof mass shifts from its nominal
position, causing an imbalance in the capacitive half-bridge. This imbalance is measured
using charge integration in response to a voltage pulse applied to the sense capacitor.
At steady state, the nominal value of the capacitors are a few pF, and when an acceleration
is applied the maximum variation of the capacitive load is in the fF range.
5.2 IC interface
The complete signal processing utilizes a fully differential structure, while the final stage
converts the differential signal into a single-ended signal to be compatible with external
applications.
The first stage is a low-noise capacitive amplifier that implements a correlated double
sampling (CDS) at its output to cancel the offset and the 1/f noise. The signal produced is
then sent to three different S&Hs, one for each channel, and made available to the outside.
All the analog parameters (output offset voltage and sensitivity) are ratiometric to the
voltage supply. Increasing or decreasing the voltage supply, the sensitivity and the offset
increases or decreases linearly. This feature provides for cancellation of the error related to
the voltage supply along an analog-to-digital conversion chain.
5.3 Factory calibration
The IC interface is factory-calibrated for sensitivity (So) and Zero-g level (Voff). The trimming
values are stored in the device in a non-volatile structure. Any time the device is turned on,
the trimming parameters are downloaded to the registers to be employed during normal
operation. This allows the user to use the device without further calibration.
Doc ID 16931 Rev 1 9/14
Page 10
Application hints LIS332AR
6 Application hints
Figure 3. LIS332AR electrical connection
6DD
/PTIONAL
8
6OU T X
6OU T Y
6OUTZ
4OP VIEW
$IRECTION
OFTHE
DETECTABLE
ACCELERATION
0ININDICATOR
9
:
S
34
0$
,)3!2
TOPVIEW
'.$
'.$
N&
'.$
P
#LOADX
#LOADY
#LOADZ
&
$IGITALSIGNALS
!-V
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 LIS332AR allows band limiting of Voutx, Vouty and Voutz through the use of external
capacitors. The recommended frequency range spans from DC up to 2.0 kHz. Capacitors
must be added at the output pins to implement low-pass filtering for anti-aliasing and noise
reduction. The equation for the cut-off frequency ( f
f
------------------------------------------------------------------------=
t
2π R
out
Taking into account that the internal filtering resistor (R
) of the external filters is:
t
1
C
load
xyz,,()⋅⋅
) has a nominal value of 32 kΩ, the
out
equation for the external filter cut-off frequency may be simplified as follows:
load
5µF
Hz[]=
xyz,,()
f
-------------------------------------- -
t
C
The tolerance of the internal resistor can vary ±15% (typ) from its nominal value of 32 kΩ;
thus the cut-off frequency will vary accordingly. A minimum capacitance of 2.5 nF for C
LOAD
(x, y, z) is required.
10/14 Doc ID 16931 Rev 1
Page 11
LIS332AR Application hints
Table 6. Filter capacitor selection, C
LOAD
Cut-off frequency Capacitor value
1 Hz 5 µF
10 Hz 0.5 µF
20 Hz 250 nF
50 Hz 100 nF
100 Hz 50 nF
200 Hz 25 nF
500 Hz 10 nF
6.1 Soldering information
The LGA package is compliant with the ECOPACK®, RoHs and “Green” standard.
It is qualified for soldering heat resistance according to JEDEC J-STD-020C.
Leave “pin 1 Indicator” unconnected during soldering.
Land pattern and soldering recommendations are available at www.st.com
6.2 Output response vs. orientation
(x,y,z)
Figure 4. Output response vs. orientation
X=1.5V (0g)
Y=2.1V (+1g)
Z=1.5V (0g)
X=2.1V (+1g)
Y=1.5V (0g)
Z=1.5V (0g)
TOP VIEW
X=1.5V (0g)
Y=0.9V (-1g)
Z=1.5V (0g)
X=0.9V (-1g)
Y=1.5V (0g)
Z=1.5V (0g)
Bottom
To p
To p
Bottom
Earth’s Surface
X=1.5V (0g)
Y=1.5V (0g)
Z=2.1V (+1g)
X=1.5V (0g)
Y=1.5V (0g)
Z=0.9V (-1g)
Figure 4 refers to the LIS332AR powered at 3 V.
Doc ID 16931 Rev 1 11/14
Page 12
Package information LIS332AR
7 Package information
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com. ECOPACK
is an ST trademark.
Figure 5. LGA-16: mechanical data and package dimensions
Dimensions
Ref.
A1 1.000 0.0394
A2 0.7850.0309
A3 0.200 0.0079
D1 2.850 3.000 3.150 0.1122 0.1181 0.1240
E1 2.850 3.000 3.150 0.1122 0.1181 0.1240
L1 1.000 1.060 0.0394 0.0417
L2 2.000 2.060 0.07870.0811
N1 0.500 0.0197
N2 1.000 0.0394
M 0.040 0.100 0.160 0.0016 0.0039 0.0063
P1 0.875 0.0344
P2 1.275 0.0502
T1 0.290 0.350 0.410 0.0114 0.0138 0.0161
T2 0.190 0.250 0.310 0.0075 0.0098 0.0122
d0.150 0.0059
k 0.050 0.0020
mm inch
Min. Typ. Max. Min. Typ. Max.
Land Grid Array Package
Outline and
mechanical data
LGA-16(3x3x1.0mm)
12/14 Doc ID 16931 Rev 1
7983231
Page 13
LIS332AR Revision history
8 Revision history
Table 7. Document revision history
Date Revision Changes
02-Feb-2010 1 Initial release.
Doc ID 16931 Rev 1 13/14
Page 14
LIS332AR
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14/14 Doc ID 16931 Rev 1
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