STMicroelectronics LIS3L02AQ5TR Mems inertial sensor: 3-axis - â±2g/â±6g linear accelerometer Datasheet

LIS3L02AQ5
MEMS INERTIAL SENSOR:
3-axis - ±2g/±6g LINEAR ACCELEROMETER
PRELIMINARY DATA
Features
■
4.5V TO 5.5V SINGLE SUPPLY OPERATION
■
LOW POWER CONSUMPTION
■
±2g/±6g USER SELECTABLE FULL-SCALE
■
0.5mg RESOLUTION OVER 100Hz
BANDWIDTH
■
EMBEDDED SELF TEST AND POWER
DOWN
■
QFN-44
to design a dedicated circuit which is trimmed to
better match the sensing element characteristics.
OUTPUT VOLTAGE, OFFSET AND
SENSITIVITY RATIOMETRIC TO THE
SUPPLY VOLTAGE
■
HIGH SHOCK SURVIVABILITY
■
ECO-PACK COMPLIANT
The LIS3L02AQ5 has a user selectable full scale
of ±2g, ±6g and it is capable of measuring
accelerations over a bandwidth of 1.5 KHz for all
axes. The device bandwidth may be reduced by
using external capacitances. A self-test capability
allows to check the mechanical and electrical
signal path of the sensor.
Description
The LIS3L02AQ5 is a low-power 3-axis linear
capacitive accelerometer that includes a sensing
element and an IC interface able to take the
information from the sensing element and 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 inertial
sensors and actuators in silicon.
The IC interface is manufactured using a standard
CMOS process that allows high level of integration
The LIS3L02AQ5 is available in plastic SMD
package and it is specified over an extended
temperature range of -40°C to +85°C.
The LIS3L02AQ5 belongs to a family of products
suitable for a variety of applications:
– Mobile terminals
– Gaming and Virtual Reality input devices
– Free-fall detection for data protection
– Antitheft systems and Inertial Navigation
– Appliance and Robotics.
Order codes
Part number
Temp range, °C
Package
Packing
LIS3L02AQ5
-40°C to +85°C
QFN-44
Tray
LIS3L02AQ5TR
-40°C to +85°C
QFN-44
Tape & Reel
July 2005
CD00059677
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to
change without notice.
Rev 1
1/15
www.st.com
15
LIS3L02AQ5
Contents
1
2
3
4
Block Diagram & Pins Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2
Pins Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Mechanical and Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1
Mechanical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4
Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1
Sensing element . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2
IC Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3
Factory calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Application hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1
Soldering information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5
Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2/15
CD00059677
LIS3L02AQ5
1 Block Diagram & Pins Description
1
Block Diagram & Pins Description
1.1
Block diagram
Figure 1.
Block Diagram
Routx Voutx
X+
CHARGE
AMPLIFIER
Y+
Z+
a
MUX
S/H
Routy Vouty
DEMUX
S/H
ZY-
Routz Voutz
XS/H
REFERENCE
SELF TEST
Pins Description
1
Y
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
NC
GND
NC
Vdd
NC
LIS3L02AQ5
Vouty
Reserved
ST
Reserved
Voutx
Reserved
CD00059677
NC
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
NC
NC
FS
NC
NC
Voutz
DIRECTION OF THE
DETECTABLE
ACCELERATIONS
NC
NC
X
NC
NC
PD
Z
NC
Pins Connection (Top view)
NC
Figure 2.
NC
1.2
CLOCK
TRIMMING CIRCUIT
3/15
LIS3L02AQ5
1 Block Diagram & Pins Description
Table 1.
4/15
Pins description
Pin #
Pin Name
Function
1 to 3
NC
4
GND
0V supply
5
Vdd
Power supply
6
Vouty
7
ST
8
Voutx
9-13
NC
Internally not connected
14
PD
Power Down (Logic 0: normal mode; Logic 1: Power-Down mode)
15
Voutz
16
FS
17-18
Reserved
Leave unconnected
19
Reserved
Leave unconnected
20
Reserved
Leave unconnected
21
NC
22-23
Reserved
24-25
NC
Internally not connected
26
Reserved
Connect to Vdd or GND
27
Reserved
Leave unconnected or connect to Vdd
28
Reserved
Leave unconnected or connect to GND
29-44
NC
Internally not connected
Output Voltage, y-channel
Self Test (Logic 0: normal mode; Logic 1: Self-test)
Output Voltage, x-channel
Output Voltage, z-channel
Full Scale selection (Logic 0: ±2g Full-scale; Logic 1: ±6g Full-scale)
Internally not connected
Leave unconnected
Internally not connected
CD00059677
LIS3L02AQ5
2 Mechanical and Electrical Specifications
2
Mechanical and Electrical Specifications
2.1
Mechanical Characteristics.
Table 2.
Mechanical Characteristics1
(Temperature range -40°C to +85°C) All the parameters are specified @ Vdd =5.0V,
T = 25°C unless otherwise noted
Symbol
Ar
So
Parameter
Acceleration Range 3
Sensitivity4
Test Condition
Min.
Typ.2
FS pin connected to
GND
±1.8
±2.0
g
FS pin connected to
Vdd
±5.4
±6.0
g
Full-scale = 2g
Vdd/5–10%
Vdd/5
Vdd/5+10%
V/g
Full-scale = 6g
Vdd/15–10%
Vdd/15
Vdd/15+10%
V/g
SoDr
Sensitivity Change Vs
Temperature
Delta from +25°C
Voff
Zero-g Level4
T = 25°C
OffDr
NL
±0.01
Vdd/2-6%
Zero-g Level Change Vs
Delta from +25°C
Temperature
Non
Linearity5
Vt
Acceleration Noise
Density
Vdd/2
Unit
%/°C
Vdd/2+6%
±0.8
V
mg/°C
Best fit straight line
Full-scale = 2g
X, Y axis
±0.3
±1.5
% FS
Best fit straight line
Full-scale = 2g
Z axis
±0.6
±2
% FS
±2
±4
%
CrossAx Cross-Axis6
An
Max.
Vdd=5.0V;
Full-scale = 2g
µg
----------Hz
50
T = 25°C
Vdd=5.0V
Full-scale = 2g
X axis
-70
-140
-320
mV
T = 25°C
Self Test Output Voltage Vdd=5.0V
Full-scale = 2g
Change7,8,9
Y axis
70
140
320
mV
T = 25°C
Vdd=5.0V
Full-scale = 2g
Z axis
70
140
320
mV
CD00059677
5/15
LIS3L02AQ5
2 Mechanical and Electrical Specifications
Table 2.
Symbol
Mechanical Characteristics1 (continued)
(Temperature range -40°C to +85°C) All the parameters are specified @ Vdd =5.0V,
T = 25°C unless otherwise noted
Parameter
Test Condition
Min.
Fres
Sensing Element
all axes
Resonance Frequency10
1.5
Top
Operating Temperature
Range
-40
Wh
Product Weight
Typ.2
Max.
Unit
KHz
+85
0.2
°C
gram
Note: 1 The product is factory calibrated at 5.0V. The device can be powered from 4.5V to 5.5V. Voff, So
and Vt parameters will vary with supply voltage.
2 Typical specifications are not guaranteed
3 Guaranteed by wafer level test and measurement of initial offset and sensitivity
4 Zero-g level and sensitivity are essentially ratiometric to supply voltage
5 Guaranteed by design
6 Contribution to the measuring output of the inclination/acceleration along any perpendicular
axis
7 Self test “output voltage change” is defined as Vout(Vst=Logic1)-Vout(Vst=Logic0)
8 Self test “output voltage change” varies cubically with supply voltage
9 When full-scale is set to ±6g, self-test “output voltage change” is one third of the specified value
10 Minimum resonance frequency Fres=1.5KHz. Sensor bandwidth=1/(2*π*110KΩ*Cload) with
Cload>1nF.
6/15
CD00059677
LIS3L02AQ5
2.2
2 Mechanical and Electrical Specifications
Electrical Characteristics
Table 3.
Symbol
Electrical Characteristics1
(Temperature range -40°C to +85°C) All the parameters are specified @ Vdd =5.0V, T=25°C
unless otherwise noted
Parameter
Test Condition
Min.
Typ.2
Max.
Unit
4.5
5.0
5.5
V
Vdd
Supply Voltage
Idd
Supply Current
mean value
PD pin connected to
GND
1.0
1.5
mA
Supply Current in Power
Down Mode
rms value
PD pin connected to Vdd
2.5
5
µA
IddPdn
Vst
Logic 0 level
0
0.8
V
Logic 1 level
2.2
Vdd
V
140
kΩ
Self Test Input
Rout
Output Impedance
80
Cload
Capacitive Load Drive3
320
Ton
Turn-On Time at Exit
From Power Down Mode
Top
Operating Temperature
Range
Cload in µF
110
pF
550*Cload+0.3
-40
ms
+85
°C
Note: 1 The product is factory calibrated at 5.0V
2 Typical specifications are not guaranteed
3 Minimum resonance frequency Fres=1.5KHz. Sensor bandwidth=1/(2*π*110KΩ*Cload) with
Cload>1nF
CD00059677
7/15
LIS3L02AQ5
2 Mechanical and Electrical Specifications
2.3
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 4.
Absolute maximum ratings
Symbol
Ratings
Vdd
Supply voltage
Vin
Input Voltage on Any Control pin (FS, PD, ST)
Maximum Value
Unit
-0.3 to 7
V
-0.3 to Vdd +0.3
V
3000g for 0.5 ms
APOW
Acceleration (Any axis, Powered, Vdd=3.3V)
AUNP
Acceleration (Any axis, Not powered)
TSTG
Storage Temperature Range
10000g for 0.1 ms
3000g for 0.5 ms
10000g for 0.1 ms
-40 to +125
°C
2KV HBM
ESD
Electrostatic Discharge Protection
200V MM
1500V CDM
This is a Mechanical Shock sensitive device, improper handling can cause
permanent damages to the part
This is an ESD sensitive device, improper handling can cause permanent damages
to the part
2.4
Terminology
Sensitivity describes the gain of the sensor and can be determined by applying 1g
acceleration to it. As the sensor can measure DC accelerations this can be done easily by
pointing the axis of interest towards the center of the earth, note the output value, rotate the
sensor by 180 degrees (point to the sky) and note the output value again thus applying ±1g
acceleration to the sensor. Subtracting the larger output value from the smaller one and dividing
the result by 2 will give the actual sensitivity of the sensor. This value changes very little over
temperature (see sensitivity change vs. temperature) and also very little over time. The
Sensitivity Tolerance describes the range of Sensitivities of a large population of sensors.
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 0g in X axis and 0g in Y axis whereas the Z
axis will measure +1g. The output is ideally for a 5.0V powered sensor Vdd/2 = 2500mV. A
deviation from ideal 0-g level (2500mV in this case) is called Zero-g offset. Offset of precise
MEMS sensors is to some extend a result of stress to the 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" - the Zero-g level of an individual sensor is very stable over lifetime. The Zero-g
level tolerance describes the range of zero-g levels of a population of sensors.
8/15
CD00059677
LIS3L02AQ5
2 Mechanical and Electrical Specifications
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.
CD00059677
9/15
LIS3L02AQ5
3 Functionality
3
Functionality
The LIS3L02AQ5 is a high performance, low-power, analog output 3-axis linear accelerometer
packaged in a QFN package. The complete device includes a sensing element and an IC
interface able to take the information from the sensing element and to provide an analog signal
to the external world.
3.1
Sensing element
A proprietary process is used to create a surface micro-machined accelerometer. The
technology allows to carry out suspended silicon structures which are attached to the substrate
in a few points called anchors and are free to move in the direction of the sensed acceleration.
To be compatible with the traditional packaging techniques a cap is placed on top of the
sensing element to avoid blocking the moving parts during the moulding phase of the plastic
encapsulation.
When an acceleration is applied to the sensor the proof mass displaces 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 few pF and when an acceleration is
applied the maximum variation of the capacitive load is up to 100fF.
3.2
IC Interface
In order to increase robustness and immunity against external disturbances the complete signal
processing chain uses a fully differential structure. The final stage converts the differential
signal into a single-ended one to be compatible with the external world.
The signals of the sensing element are multiplexed and fed into a low-noise capacitive charge
amplifier that implements a Correlated Double Sampling system (CDS) at its output to cancel
the offset and the 1/f noise. The output signal is de-multiplexed and transferred to three
different S&Hs, one for each channel and made available to the outside.
The low noise input amplifier operates at 200 kHz while the three S&Hs operate at a sampling
frequency of 66 kHz. This allows a large oversampling ratio, which leads to in-band noise
reduction and to an accurate output waveform.
All the analog parameters (zero-g level, sensitivity and self-test) are ratiometric to the supply
voltage. Increasing or decreasing the supply voltage, the sensitivity and the offset will increase
or decrease almost linearly. The self test voltage change varies cubically with the supply
voltage.
3.3
Factory calibration
The IC interface is factory calibrated for sensitivity (So) and Zero-g level (Voff).
The trimming values are stored inside the device by a non volatile structure. Any time the
device is turned on, the trimming parameters are downloaded into the registers to be employed
during the normal operation. This allows the user to employ the device without further
calibration.
10/15
CD00059677
LIS3L02AQ5
4
4 Application hints
Application hints
Figure 3.
LIS3L02AQ5 Electrical Connection
Vdd
44
1
33
GND
Z
GND
LIS3L02AQ5
ST
GND
1
Y
(top view)
GND
23res
11
X
res
res
res
res
22
12
FS res
GND
100nF
PD
10µF
Vdd
34
Optional
Vout Z
Cload z
DIRECTION OF THE
DETECTABLE
ACCELERATIONS
Optional
Vout X
Cload x
Optional
Vout Y
Cload y
Digital signals
Power supply decoupling capacitors (100nF ceramic or polyester + 10µF Aluminum) should be
placed as near as possible to the device (common design practice).
The LIS3L02AQ5 allows to band limit Voutx, Vouty and Voutz through the use of external
capacitors. The re-commended frequency range spans from DC up to 1.5 KHz. 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 (ft) of the external filters is:
1
f t = --------------------------------------------------------------2π ⋅ R ou t ⋅ C lo ad ( x, y, z )
Taking into account that the internal filtering resistor (Rout) has a nominal value equal to
110kOhm, the equation for the external filter cut-off frequency may be simplified as follows:
1.45µF
f t = ----------------------------------C loa d ( x, y, z )
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 320 pF for
Cf(x, y, z) is required in any case.
CD00059677
11/15
LIS3L02AQ5
4 Application hints
Table 5.
4.1
Filter Capacitor Selection, Cf (x,y,z). Commercial capacitance value choose.
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
Soldering information
The QFN44 package is lead free and green package qualified for soldering heat resistance
according to JEDEC J-STD-020C. Land pattern and soldering recommendations are available
upon request.
12/15
CD00059677
LIS3L02AQ5
Figure 4.
Package Information
QFN-44 Mechanical Data & Package Dimensions
mm
inch
OUTLINE AND
MECHANICAL DATA
DIM.
MIN.
TYP.
MAX.
MIN.
TYP.
MAX.
A
1.70
1.80
1.90
0.067
0.071
0.075
A1
0.19
0.21
0.007
b
0.20
0.30
0.008
0.25
0.008
0.01
D
7.0
0.276
E
7.0
0.276
e
0.50
0.020
0.012
J
5.04
5.24
0.198
0.206
K
5.04
5.24
0.198
0.206
L
0.38
0.58
0.015
P
0.48
45 REF
0.019
0.023
QFN-44 (7x7x1.8mm)
Quad Flat Package No lead
45 REF
SEATING PLANE
5
5 Package Information
M
G
M
N
34
44
44
1
33
1
DETAIL "N"
23
11
22
12
DETAIL G
CD00059677
13/15
LIS3L02AQ5
6 Revision history
6
14/15
Revision history
Date
Revision
14-July-2005
1
Changes
First issue.
CD00059677
LIS3L02AQ5
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted
by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject
to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not
authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.
The ST logo is a registered trademark of STMicroelectronics.
All other names are the property of their respective owners
© 2005 STMicroelectronics - All rights reserved
STMicroelectronics group of companies
Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America
www.st.com
CD00059677
15/15
Similar pages