LIS3L02AQ3TR - STMicroelectronics

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LIS3L02AQ3

May 2005

1 Features

■2.4V TO 3.6V SINGLE SUPPLY OPERATION

■LOW POWER CONSUMPTION

■±2g/±6g USER SELECTABLE FULL-SCALE

■BETTER THAN 0.5mg RESOLUTION OVER

100Hz BANDWIDTH

■EMBEDDED SELF TEST AND POWER DOWN

■OUTPUT VOLTAGE, OFFSET AND

SENSITIVITY RATIOMETRIC TO THE

SUPPLY VOLTAGE

■HIGH SHOCK SURVIVABILITY

■ECO-PACK COMPLIANT

2 Description

The LIS3L02AQ3 is a low-power 3-Axis linear capac-

itive 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 accel-

eration, is manufactured using a dedicated process

developed by ST to produce inertial sensors and ac-

tuators in silicon.

The IC interface is manufactured using a standard

CMOS process that allows high level of integration to

design a dedicated circuit which is trimmed to better

match the sensing element characteristics.

The LIS3L02AQ3 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 capac-

itances. A self-test capability allows to check the me-

chanical and electrical signal path of the sensor.

The LIS3L02AQ3 is available in plastic SMD pack-

age and it is specified over an extended temperature

range of -40°C to +85°C.

The LIS3L02AQ3 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

MEMS INERTIAL SENSOR:

3-Axis - ±2g/±6g LINEAR ACCELEROMETER

Figure 2. Block Diagram

DEMUX

S/H

CHARGE

AMPLIFIER

S/H

MUX

Y+

Z+

Y-

Z-

Voutx

Voutz

Routx

Routz

TRIMMING CIRCUIT CLOCK

S/H

Vouty

Routy

X+

X-

SELF TEST

REFERENCE

Figure 1. Package

Table 1. Order Codes

Part Number Package Finishing

LIS3L02AQ3 QFN-44 TRAY

LIS3L02AQ3TR QFN-44 TAPE & REEL

QFN-44

Rev. 2

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Table 2. Pin Description

Figure 3. Pin Connection (Top view)

N° Pin Function

1 to 3 NC Internally not connected

4 GND 0V supply

5 Vdd Power supply

6 Vouty Output Voltage, y-channel

7 ST Self Test (Logic 0: normal mode; Logic 1: Self-test)

8 Voutx Output Voltage, x-channel

9-13 NC Internally not connected

14 PD Power Down (Logic 0: normal mode; Logic 1: Power-Down mode)

15 Voutz Output Voltage, z-channel

16 FS Full Scale selection (Logic 0: ±2g Full-scale; Logic 1: ±6g Full-scale)

17-18 Reserved Leave unconnected

19 Reserved Leave unconnected

20 Reserved Leave unconnected

21 NC Internally not connected

22-23 Reserved Leave unconnected

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

DIRECTION OF THE

DETECTABLE

ACCELERATIONS

GND

Vdd

Vouty

Voutx

Reserved

Voutz

Reserved

LIS3L02AQ3

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Notes: 1. The product is factory calibrated at 3.3V. The device can be powered from 2.4V to 3.6V. 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.

Table 3. Mechanical Characteristics1

(Temperature range -40°C to +85°C) All the parameters are specified @ Vdd =3.3V, T=25°C unless oth-

erwise noted

Symbol Parameter Test Condition Min. Typ.2Max. Unit

Ar Acceleration Range3FS pin connected

to GND

±1.8 ±2.0 g

FS pin connected

to Vdd

±5.4 ±6.0 g

So Sensitivity4Full-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 ±0.01 %/°C

Voff Zero-g Level4T = 25°C Vdd/2-6% Vdd/2 Vdd/2+6% V

OffDr Zero-g Level Change Vs

Temperature

Delta from +25°C ±0.8 mg/°C

NL Non Linearity5Best 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

CrossAx Cross-Axis6±2±4%

An Acceleration Noise Density Vdd=3.3V;

Full-scale = 2g

50 µg/

Vt Self Test Output Voltage

Change7,8,9

T = 25°C

Vdd=3.3V

Full-scale = 2g

X axis

-20 -50 -100 mV

T = 25°C

Vdd=3.3V

Full-scale = 2g

Y axis

20 50 100 mV

T = 25°C

Vdd=3.3V

Full-scale = 2g

Z axis

20 50 100 mV

Fres Sensing Element Resonance

Frequency10

all axes 1.5 KHz

Top Operating Temperature

Range

-40 +85 °C

Wh Product Weight 0.2 gram

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Notes: 1. The product is factory calibrated at 3.3V.

2. Typical specifications are not guaranteed

3. Minimum resonance frequency Fres=1.5KHz. Sensor bandwidth=1/(2*π*110KΩ*Cload) with Cload>1nF

3 Absolute Maximum Rating

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 Rating

This is a ESD sensitive device, improper handling can cause permanent damages to the part.

This is a mechanical shock sensitive device, improper handling can cause permanent damages to the

part.

Table 4. Electrical Characteristics1

(Temperature range -40°C to +85°C) All the parameters are specified @ Vdd =3.3V, T=25°C unless

otherwise noted

Symbol Parameter Test Condition Min. Typ.2Max. Unit

Vdd Supply Voltage 2.4 3.3 3.6 V

Idd Supply Current mean value

PD pin connected

to GND

0.85 1.5 mA

IddPdn Supply Current in Power

Down Mode

rms value

PD pin connected

to Vdd

25µA

Vst Self Test Input Logic 0 level 0 0.8 V

Logic 1 level 2.2 Vdd V

Rout Output Impedance 80 110 140

Ω

Cload Capacitive Load Drive3320 pF

Ton Turn-On Time at Exit From

Power Down Mode

Cload in µF550*Cload

+0.3

Top Operating Temperature

Range

-40 +85 °C

Symbol Ratings Maximum Value Unit

Vdd Supply voltage -0.3 to 7 V

Vin Input Voltage on Any Control pin (FS, PD, ST) -0.3 to Vdd +0.3 V

APOW Acceleration (Any axis, Powered, Vdd=3.3V) 3000g for 0.5 ms

10000g for 0.1 ms

AUNP Acceleration (Any axis, Not powered) 3000g for 0.5 ms

10000g for 0.1 ms

TSTG Storage Temperature Range -40 to +125 °C

ESD Electrostatic Discharge Protection 2KV HBM

200V MM

1500V CDM

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3.1 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 3.3V powered sensor Vdd/2 = 1650mV. A deviation from ideal 0-g level

(1650mV 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 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 deflec-

tion 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 resis-

tor 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 frequen-

cy 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.

4 Functionality

The LIS3L02AQ3 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.

4.1 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.

4.2 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

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be compatible with the external world.

The signals of the sensing element are multiplexed and fed into a low-noise capacitive charge amplifier that im-

plements 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 avail-

able 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

4.3 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.

5 Application Hints

Figure 4. LIS3L02AQ3 Electrical Connection

Power supply decoupling capacitors (100nF ceramic or polyester + 10

F Aluminum) should be placed as near

as possible to the device (common design practice).

The LIS3L02AQ3 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

res

Vout Z

Vout Y

100nF

Cload z

LIS3L02AQ3

Vdd

Vout X

GND

Vdd

GND

DIRECTION OF THE

DETECTABLE

ACCELERATIONS

Cload x

Cload y

res

(top view)

Optional

Digital signals

GND

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) of the external filters is:

Taking in account that the internal filtering resistor (R

out

) has a nominal value equal to 110k

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 ±20% within its nominal value of 110k

Ω

; thus the cut-

off frequency will vary accordingly. A minimum capacitance of 320 pF

for C

(x,y,z) is required in any case.

Table 6. Filter Capacitor Selection,

(

x,y,z

). Commercial capacitance value choose.

5.1 Soldering information

The QFN44 package is lead free and green package qualified for soldering heat resistance according to JEDEC

J-STD-020D. Land pattern and soldering recommendations are available upon request.

Cut-off frequency

(Hz)

Capacitor value

(nF)

11500

10 150

50 30

100 15

200 6.8

500 3

2πRout Cload xyz,,()⋅⋅

---------------------------------------------------------------=

1.45µF

Cload xyz,,()

-----------------------------------=

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6 Typical performance characteristics

6.1 Mechanical Characteristics at 25°C

Figure 5. x-axis 0-g level at 3.3V

Figure 6. y-axis 0-g level at 3.3V

Figure 7. z-axis 0-g level at 3.3V

Figure 8. x-axis sensitivity at 3.3V

Figure 9. y-axis sensitivity at 3.3V

Figure 10. z-axis sensitivity at 3.3V

1.55 1.6 1.65 1.7 1.75

0g LEVEL (V)

Percent of parts (%)

1.55 1.6 1.65 1.7 1.75

0g LEVEL (V)

Percent of parts (%)

1.55 1.6 1.65 1.7 1.75

0g LEVEL (V)

Percent of parts (%)

0.62 0.63 0.64 0.65 0.66 0.67 0.68 0.69 0.7

sensitivity (V/g)

Percent of parts (%)

0.62 0.63 0.64 0.65 0.66 0.67 0.68 0.69 0.7

sensitivity (V/g)

Percent of parts (%)

0.62 0.63 0.64 0.65 0.66 0.67 0.68 0.69 0.7

sensitivity (V/g)

Percent of parts (%)

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6.2 Mechanical Characteristics derived from measurement in the -40

°C

to +85

°C

temperature range

Figure 11. x-axis 0-g level change vs.

temperature

Figure 12. y-axis 0-g level change vs.

temperature

Figure 13. z-axis 0-g level change vs.

temperature

Figure 14. x-axis sensitivity change vs.

temperature

Figure 15. y-axis sensitivity change vs.

temperature

Figure 16. z-axis sensitivity change vs.

temperature

2 1.5 1 0.5 0

Zerog level change (mg/ οC)

Percent of parts (%)

1.5 1 0.5 0 0.5

Zerog level change (mg/ οC)

Percent of parts (%)

3.5 3 2.5 2 1.5 1 0.5 0 0.5

Zerog level change (mg/ οC)

Percent of parts (%)

0.025 0.02 0.015 0.01 0.005 0 0.005

sensitivity change (%/

Percent of parts (%)

0.025 0.02 0.015 0.01 0.005 0 0.005

sensitivity change (%/οC)

Percent of parts (%)

0.03 0.025 0.02 0.015 0.01 0.005 0

sensitivity change (%/οC)

Percent of parts (%)

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6.3 Electrical characteristics at 25°C

Figure 17. Noise density at 3.3V (x,y axes)

Figure 18. Noise density at 3.3V (z axis)

Figure 19. Current consumption at 3.3V

Figure 20. Current consumption in power

down mode at 3.3V

18 20 22 24 26 28 30 32

Noise density (ug/sqrt(Hz))

Percent of parts (%)

20 30 40 50 60 70 80

Noise density (ug/sqrt(Hz))

Percent of parts (%)

0.4 0.6 0.8 1 1.2 1.4

current consumption (mA)

Percent of parts (%)

1.2 1.3 1.4 1.5 1.6 1.7 1.8

current consumption (uA)

Percent of parts (%)

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7 Package Information

Figure 21. QFN-44 Mechanical Data & Package Dimensions

OUTLINE AND

MECHANICAL DATA

DIM.

mm inch

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 0.008

b 0.20 0.25 0.30 0.008 0.01 0.012

D 7.0 0.276

E 7.0 0.276

e 0.50 0.020

J 5.04 5.24 0.198 0.206

K 5.04 5.24 0.198 0.206

L 0.38 0.48 0.58 0.015 0.019 0.023

P 45 REF 45 REF

QFN-44 (7x7x1.8mm)

Quad Flat Package No lead

DETAIL "N"

34 44

22 12

DETAIL G

SEATING PLANE

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8 Revision History

Table 7. Revision History

Date Revision Description of Changes

November 2004 1 First Issue.

May 2005 2 Major datasheet review.

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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.

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