high performance 3-axis ±2/±6g ultracompact linear accelerometer
Features
■ 2.4 V to 3.6 V single supply operation
■ ±2 g / ±6 g user selectable full-scale
■ Low power consumption
■ Output voltage, offset and sensitivity are
ratiometric to the supply voltage
■ Factory trimmed device sensitivity and offset
■ Embedded self test
■ RoHS/ECOPACK
■ High shock survivability ( 10000 g )
®
compliant
Description
The LIS344ALH is an ultra compact consumer
low-power three-axis linear 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 an ST
proprietary CMOS process with high level of
integration. The dedicated circuit is trimmed to
better match the sensing element characteristics.
LGA 16L
The LIS344ALH has a dynamically user
selectable full-scale of ±2 g / ±6 g and it is
capable of measuring accelerations over a
maximum bandwidth of 1.8 kHz for all axes. The
device bandwidth may be reduced by using
external capacitances. The self-test capability
allows the user to check the functioning of the
system.
The LIS344ALH is available in Land Grid Array
package (LGA) manufactured by ST.
It is guaranteed to operate over an extended
temperature range of -40 °C to +85 °C.
The LIS344ALH belongs to a family of products
suitable for a variety of applications:
– Mobile terminals
– Gaming and virtual reality input devices
– Antitheft systems and inertial navigation
– Appliance and robotics.
2STSelf test (logic 0: normal mode; logic 1: self-test mode)
3NCInternally not connected
4ResLeave unconnected or connect to Vdd
5PDPower down (logic 0: normal mode; logic 1: power-down mode)
6NCInternally not connected
7GND0 V supply
8VoutZOutput voltage Z channel
9NCInternally not connected
10VoutYOutput voltage Y channel
11NCInternally not connected
12VoutXOutput voltage X channel
13NCInternally not connected
14VddPower supply
15ResConnect to Vdd
16NCInternally not connected
6/19
Page 7
LIS344ALHMechanical and electrical specifications
2 Mechanical and electrical specifications
2.1 Mechanical characteristics
Table 3.Mechanical characteristics @ Vdd =3.3 V, T = 25 °C unless otherwise noted
SymbolParameterTest conditionMin. Typ.
ArAcceleration range
FS pin connected to
(3)
GND
±1.8± 2
(2)
Max.Unit
(1)
FS pin connected to Vdd±5.4± 6
SoSensitivity
(4)
Full-scale = ±2 gVdd/5 - 5%Vdd/5Vdd/5 + 5%
Full-scale = ±6 gVdd/15 - 10%Vdd/15Vdd/15 + 10%
SoDr
VoffZero-g level
OffDr
CrossAx Cross-axis
Fres
Top
Sensitivity change Vs
Temperature
Zero-g level change Vs
Temperature
NLNon linearity
Acceleration noise
An
density
Self test output voltage
Vt
change
(7),(8),(9)
Sensing element
resonant frequency
Operating temperature
range
(6)
(4)
(5)
Delta from +25 °C± 0.01%/°C
Full-scale = ±2 g
T = 25 °C
Vdd/2 - 5%Vdd/2Vdd/2 + 5%V
Delta from +25 °C±0.4mg/°C
Best fit straight line
Full-scale = ±2 g
±0.5% FS
±2%
Vdd = 3.3 V;
Full-scale = ±2 g
X axis
T = 25 °C; Vdd=3.3 V
Y axis
T = 25 °C; Vdd=3.3 V
Z axis
T = 25 °C; Vdd=3.3 V
X,Y,Z axis1.8KHz
(10)
80140200mV
-200-140-80mV
100230350mV
50µg/
-40+85°C
WhProduct weight0.040gram
1. The product is factory calibrated at 3.3 V. The operational power supply range is from 2.4 V to 3.6 V. 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 at the calibration level ±8%.
5. Guaranteed by design.
6. Contribution to the measuring output of an inclination/acceleration along any perpendicular axis.
7. “Self test output voltage change” is defined as Vout
8. “Self test output voltage change” varies cubically with supply voltage.
9. When full-scale is set to ±6 g, “Self test output voltage change” is one third of the specified value at ±2 g.
10. Minimum resonance frequency Fres=1.8 kHz. Sensor bandwidth=1/(2*π*110kΩ*Cload), with Cload>1 nF.
(Vst=Logic1)
-Vout
(Vst=Logic0)
.
g
V/g
Hz
7/19
Page 8
Mechanical and electrical specificationsLIS344ALH
2.2 Electrical characteristics
Table 4.Electrical characteristics @ Vdd =3.3 V, T = 25 °C unless otherwise noted
SymbolParameterTest conditionMin.Typ.
(2)
(1)
Max.Unit
VddSupply voltage2.43.33.6V
Normal mode680850
IddSupply current
Power-down mode15
Vfs
Vst
Vpd
Rout
Cload
To n
To p
1. The product is factory calibrated at 3.3 V.
2. Typical specifications are not guaranteed.
3. Minimum resonance frequency Fres=1.8 kHz. Device bandwidth=1/(2*π*110 kΩ*Cload), with Cload>1 nF.
Full-scale input
Self-test input
Power-down input
Output impedance of
VoutX, VoutY, VoutZ
Capacitive load drive
for VoutX, VoutY, VoutZ
Turn-on time at exit of
Power-down mode
Operating temperature
range
Logic 0 level00.3*VddV
Logic 1 level0.7*VddVddV
90110130KΩ
(3)
1nF
Cload expressed in µF
550*Cload+
0.3
-40+85ºC
µA
ms
8/19
Page 9
LIS344ALHMechanical 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 5.Absolute maximum ratings
SymbolRatingsMaximum valueUnit
VddSupply voltage-0.3 to 7V
VinInput voltage on any control pin (FS, ST, PD) -0.3 to Vdd +0.3V
A
A
Acceleration (any axis, powered, Vdd = 3.3 V)
POW
Acceleration (any axis, not powered)
UNP
3000 g for 0.5 ms
10000 g for 0.1 ms
3000 g for 0.5 ms
10000 g for 0.1 ms
T
ESDElectrostatic discharge protection
Storage temperature range-40 to +125°C
STG
4 (HBM)KV
1.5 (CDM)KV
400 (MM)V
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
9/19
Page 10
Mechanical and electrical specificationsLIS344ALH
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 0 g in X axis and 0 g in Y axis whereas
the Z axis will measure 1g. The output is ideally for a 3.3 V powered sensor Vdd/2 = 1650
mV. A deviation from ideal 0-g level (1650 mV 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.
Self test allows to test the mechanical and electric part of the sensor, allowing the seismic
mass to be moved by means of an electrostatic test-force. The Self Test function is off when
the ST pin is connected to GND. When the ST pin is tied at Vdd an actuation force is applied
to the sensor, simulating a definite input acceleration. In this case the sensor outputs will
exhibit a voltage change in their DC levels which is related to the selected full-scale and
depending on the supply voltage through the device sensitivity. 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 inside Ta bl e 3 , then the sensor is working properly and the
parameters of the interface chip are within the defined specification.
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 1 nF 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 close to the resonance frequency of
the sensor. In general the smallest possible bandwidth for a particular application should be
chosen to get the best results.
10/19
Page 11
LIS344ALHFunctionality
3 Functionality
The LIS344ALH is an ultra compact low-power, analog output three-axis linear
accelerometer packaged in a LGA 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 in the fF range.
3.2 IC interface
The complete signal processing uses a fully differential structure, while the final stage
converts the differential signal into a single-ended one to be compatible with the external
world.
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 produced signal 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 will
increase or decrease linearly. This feature provides the cancellation of the error related to
the voltage supply along an analog to digital conversion chain.
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.
11/19
Page 12
Application hintsLIS344ALH
4 Application hints
Figure 3.LIS344ALH electrical connection
Vdd
µ
F
Optional
Optional
Vout x
Vout y
1
X
Optional
Vout z
(TOP VIEW)
DIRECTIONS OF THE
DETECTABLE
ACCELERATIONS
µF Aluminum)
FS
ST
16
15 14 13
1
2
LIS344ALH
(top view)
3
4
5
67
PD
GND
Digital signals
GND
100nF
8
12
11
10
9
GND
10
Cload X
Cload Y
Cload Z
Power supply decoupling capacitors (100 nF ceramic or polyester + 10
should be placed as near as possible to the device (common design practice).
Z
Pin 1 indicator
Y
The LIS344ALH allows to band limit VoutX, VoutY and VoutZ through the use of external
capacitors. The recommended frequency range spans from DC up to 1.8 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
110 KΩ, the equation for the external filter cut-off frequency may be simplified as follows:
f
t
The tolerance of the internal resistor can vary typically of
110 KΩ; thus the cut-off frequency will vary accordingly. A minimum capacitance of 1 nF for
C
(x, y, z) is required.
load
12/19
1
outCload
1.45µF
-------------------------------------- -
C
xyz,,()
load
) of the external
t
xyz,,()⋅⋅
) has a nominal value equal to
out
Hz[]=
±20% within its nominal value of
Page 13
LIS344ALHApplication hints
Table 6.Filter capacitor selection, C
Cut-off frequencyCapacitor value
1 Hz1500 nF
10 Hz150 nF
20 Hz68 nF
50 Hz30 nF
100 Hz15 nF
200 Hz6.8 nF
500 Hz3 nF
4.1 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/mems
load
(x, y, z),
.
4.2 Output response vs orientation
Figure 4.Output response vs orientation
X=2.31V (+1g)
Y=1.65V (0g)
Z=1.65V (0g)
X=1.65V (0g)
Y=0.99V (-1g)
Z=1.65V (0g)
Figure 4 shows output voltage values of LIS344ALH, powered at 3.3 V, with full-scale ±2 g.
X=1.65V (0g)
Y=2.31V (+1g)
Z=1.65V (0g)
X=0.99V (-1g)
Y=1.65V (0g)
Z=1.65V (0g)
Bottom
To p
To p
Bottom
X=1.65V (0g)
Y=1.65V (0g)
Z=0.99V (-1g)
X=1.65V (0g)
Y=1.65V (0g)
Z=2.31V (+1g)
Earth’s Surface
13/19
Page 14
Typical performance characteristicsLIS344ALH
5 Typical performance characteristics
5.1 Mechanical characteristics at 25 °C
Figure 5.X axis Zero-g level at 3.3 V Figure 6.X axis Sensitivity at 3.3 V
Figure 19. Noise density at 3.3 V (X, Y axis) Figure 20. Noise density at 3.3 V (Z axis)
30
25
20
15
30
25
20
15
Frequency of parts [%]
10
5
0
1820222426283032
Noise Density [/mug/sqrt(Hz)]
Frequency of parts [%]
10
5
0
1020304050607080
Noise Density [/mug/sqrt(Hz)]
16/19
Page 17
LIS344ALHPackage information
6 Package information
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second level Interconnect is marked on the inner box label, in compliance with JEDEC
Standard JESD97. The maximum ratings related to soldering conditions are also marked on
the inner box label. ECOPACK
ECOPACK
®
specifications are available at: www.st.com.
Figure 21. LGA 16L: mechanical data and package dimensions
Dimensions
Ref.
A11.500 1.6000.05910.0630
A21.3300.0524
A30.160 0.200 0.240 0.0063 0.0079 0.0094
d0.3000.0118
D13.850 4.000 4.150 0.1516 0.1575 0.16
E13.850 4.000 4.150 0.1516 0.1575 0.16
L21.9500.0768
M0.1000.0039
N10.6500.0256
N20.9750.0384
P11.7500.0689
P21.5250.0600
T10.4000.0157
T20.3000.0118
k0.0500.0020
mminch
Min. Typ. Max. Min. Typ. Max.
®
is an ST trademark.
34
34
Outline and
mechanical data
LGA 16L (4x4x1.5mm)
Land Grid Array Package
7974136
17/19
Page 18
Revision historyLIS344ALH
7 Revision history
Table 7.Document revision history
DateRevisionChanges
15-Jan-20081Initial release.
18-Feb-20082Minor text changes
Updated Section 2: Mechanical and electrical specifications and
29-Apr-20083
added distribution graphs in Section 5: Typical performance
characteristics
18/19
Page 19
LIS344ALH
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