Precision ±1.7 g Single-/Dual-Axis
i MEMS® Accelerometer
ADXL103/ADXL203
Rev. A
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FEATURES
High performance, single-/dual-axis accelerometer
on a single IC chip
5 mm × 5 mm × 2 mm LCC package
1 mg resolution at 60 Hz
Low power: 700 μA at VS = 5 V (typical)
High zero g bias stability
High sensitivity accuracy
–40°C to +125°C temperature range
X and Y axes aligned to within 0.1° (typical)
BW adjustment with a single capacitor
Single-supply operation
3500 g shock survival
RoHS-compliant
Compatible with Sn/Pb- and Pb-free solder processes
APPLICATIONS
Vehicle dynamic control (VDC)/electronic stability program
(ESP) systems
Electronic chassis control
Electronic braking
Platform stabilization/leveling
Navigation
Alarms and motion detectors
High accuracy, 2-axis tilt sensing
GENERAL DESCRIPTION
The ADXL103/ADXL203 are high precision, low power,
complete single- and dual-axis accelerometers with signal
conditioned voltage outputs, all on a single, monolithic IC.
The ADXL103/ADXL203 measure acceleration with a full-scale
range of ±1.7 g. The ADXL103/ADXL203 can measure both
dynamic acceleration (for example, vibration) and static
acceleration (for example, gravity).
The typical noise floor is 110 g/√Hz, allowing signals below
1 mg (0.06° of inclination) to be resolved in tilt sensing
applications using narrow bandwidths (<60 Hz).
The user selects the bandwidth of the accelerometer using
Capacitor CX and Capacitor CY at the XOUT and YOUT pins.
Bandwidths of 0.5 Hz to 2.5 kHz may be selected to suit the
application.
The ADXL103 and ADXL203 are available in 5 mm × 5 mm ×
2 mm, 8-pad hermetic LCC packages.
FUNCTIONAL BLOCK DIAGRAM
ADXL103
SENSOR
+5V
OUTPUT
AMP
COM ST XOUT
VS
CDC
CX
RFILT
32kΩ
DEMOD
AC
AMP
ADXL203
SENSOR
+5V
OUTPUT
AMP OUTPUT
AMP
COM ST YOUT
VS
CDC
CY
RFILT
32kΩ
DEMOD
XOUT
CX
RFILT
32kΩ
AC
AMP
03757-001
Figure 1.
ADXL103/ADXL203
Rev. A | Page 2 of 12
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
General Description......................................................................... 1
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
ESD Caution.................................................................................. 4
Pin Configurations and Function Descriptions ........................... 5
Typical Performance Characteristics ............................................. 6
Theory of Operation ........................................................................ 9
Performance.................................................................................. 9
Applications..................................................................................... 10
Power Supply Decoupling......................................................... 10
Setting the Bandwidth Using CX and CY................................. 10
Self Test........................................................................................ 10
Design Trade-Offs for Selecting Filter Characteristics:
The Noise/BW Trade-Off.......................................................... 10
Using the ADXL103/ADXL203 with Operating Voltages
Other than 5 V............................................................................ 11
Using the ADXL203 as a Dual-Axis Tilt Sensor .................... 11
Outline Dimensions....................................................................... 12
Ordering Guide .......................................................................... 12
REVISION HISTORY
3/06—Rev. 0 to Rev. A
Changes to Features.......................................................................... 1
Changes to Table 1............................................................................ 3
Changes to Figure 2.......................................................................... 4
Changes to Figure 3 and Figure 4................................................... 5
Changes to the Performance Section............................................. 9
4/04—Revision 0: Initial Version
ADXL103/ADXL203
Rev. A | Page 3 of 12
SPECIFICATIONS
TA = −40°C to +125°C, VS = 5 V, CX = CY = 0.1 F, acceleration = 0 g, unless otherwise noted.
Table 1.
Parameter Conditions Min1Typ Max1Unit
SENSOR INPUT Each axis
Measurement Range2 ±1.7
g
Nonlinearity % of full scale ±0.2 ±1.25 %
Package Alignment Error ±1 Degrees
Alignment Error (ADXL203) X sensor to Y sensor ±0.1 Degrees
Cross-Axis Sensitivity ±1.5 ±3 %
SENSITIVITY (RATIOMETRIC)3Each axis
Sensitivity at XOUT, YOUT V
S = 5 V 960 1000 1040 mV/g
Sensitivity Change Due to Temperature4VS = 5 V ±0.3 %
ZERO g BIAS LEVEL (RATIOMETRIC) Each axis
0 g Voltage at XOUT, YOUT V
S = 5 V 2.4 2.5 2.6 V
Initial 0 g Output Deviation from Ideal VS = 5 V, 25°C ±25 mg
0 g Offset vs. Temperature ±0.1 ±0.8 mg/°C
NOISE PERFORMANCE
Output Noise <4 kHz, VS = 5 V 1 3 mV rms
Noise Density 110 μg/√Hz rms
FREQUENCY RESPONSE5
CX, CY Range6 0.002 10 μF
RFILT Tolerance 24 32 40 kΩ
Sensor Resonant Frequency 5.5 kHz
SELF TEST7
Logic Input Low 1 V
Logic Input High 4 V
ST Input Resistance to Ground 30 50 kΩ
Output Change at XOUT, YOUT Self Test 0 to Self Test 1 450 750 1100 mV
OUTPUT AMPLIFIER
Output Swing Low No load 0.05 0.2 V
Output Swing High No load 4.5 4.8 V
POWER SUPPLY
Operating Voltage Range 3 6 V
Quiescent Supply Current 0.7 1.1 mA
Turn-On Time8 20 ms
1 All minimum and maximum specifications are guaranteed. Typical specifications are not guaranteed.
2 Guaranteed by measurement of initial offset and sensitivity.
3 Sensitivity is essentially ratiometric to VS. For VS = 4.75 V to 5.25 V, sensitivity is 186 mV/V/g to 215 mV/V/g.
4 Defined as the output change from ambient-to-maximum temperature or ambient-to-minimum temperature.
5 Actual frequency response controlled by user-supplied external capacitor (CX, CY).
6 Bandwidth = 1/(2 × π × 32 kΩ × C). For CX, CY = 0.002 μF, bandwidth = 2500 Hz. For CX, CY = 10 μF, bandwidth = 0.5 Hz. Minimum/maximum values are not tested.
7 Self-test response changes cubically with VS.
8 Larger values of CX, CY increase turn-on time. Turn-on time is approximately 160 × CX or CY + 4 ms, where CX, CY are in μF.
ADXL103/ADXL203
Rev. A | Page 4 of 12
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
Acceleration (Any Axis, Unpowered) 3500 g
Acceleration (Any Axis, Powered) 3500 g
Drop Test (Concrete Surface) 1.2 m
VS −0.3 V to +7.0 V
All Other Pins (COM − 0.3 V) to
(VS + 0.3 V)
Output Short-Circuit Duration
(Any Pin to Common) Indefinite
Temperature Range (Powered) −55°C to +125°C
Temperature Range (Storage) −65°C to +150°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Table 3. Package Characteristics
Package Type θJA θ
JC Device Weight
8-Lead CLCC 120°C/W 20°C/W <1.0 gram
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
t
P
t
L
t
25°C TO PEAK
t
S
PREHEAT
CRITICAL ZONE
T
L
TO T
P
TEMPERATURE
TIME
RAMP-DOWN
RAMP-UP
T
SMIN
T
SMAX
T
P
T
L
03757-002
Condition
Profile Feature Sn63/Pb37 Pb-Free
Average Ramp Rate (TL to TP) 3°C/second max
Preheat
• Minimum Temperature (TSMIN) 100°C 150°C
• Maximum Temperature (TSMAX) 150°C 200°C
• Time (TSMIN to TSMAX) (tS) 60 to 120 seconds 60 to 150 seconds
TSMAX to TL
• Ramp-Up Rate 3°C/second
Time Maintained above Liquidous (TL)
• Liquidous Temperature (TL) 183°C 217°C
• Time (tL) 60 to 150 seconds 60 to 150 seconds
Peak Temperature (TP) 240°C + 0°C/−5°C 260°C + 0°C/−5°C
Time Within 5°C of Actual Peak Temperature (tP) 10 to 30 seconds 20 to 40 seconds
Ramp-Down Rate 6°C/second max
Time 25°C to Peak Temperature 6 minutes max 8 minutes max
Figure 2. Recommended Soldering Profile
ADXL103/ADXL203
Rev. A | Page 5 of 12
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
ADXL103E
TOP VIEW
(Not to Scale)
ST 1
DNC 2
COM 3
DNC
4
XOUT
DNC
DNC
7
6
5
VS
+X
8
03757-022
Figure 3. ADXL103 Pin Configuration
Table 4. ADXL103 Pin Function Descriptions
Pin No. Mnemonic Description
1 ST Self Test
2 DNC Do Not Connect
3 COM Common
4 DNC Do Not Connect
5 DNC Do Not Connect
6 DNC Do Not Connect
7 XOUT X Channel Output
8 VS 3 V to 6 V
ADXL203E
TOP VIEW
(Not to Scale)
ST
1
DNC
2
COM
3
DNC
4
X
OUT
Y
OUT
DNC
7
6
5
V
S
8
03757-023
+X+Y
Figure 4. ADXL203 Pin Configuration
Table 5. ADXL203 Pin Function Descriptions
Pin No. Mnemonic Description
1 ST Self Test
2 DNC Do Not Connect
3 COM Common
4 DNC Do Not Connect
5 DNC Do Not Connect
6 YOUT Y Channel Output
7 XOUT X Channel Output
8 VS 3 V to 6 V
ADXL103/ADXL203
Rev. A | Page 6 of 12
TYPICAL PERFORMANCE CHARACTERISTICS
VS = 5 V for all graphs, unless otherwise noted.
PERCENT OF POPULATION (%)
0
25
20
15
10
5
VOLTS
–0.10
–0.08
–0.06
–0.04
–0.02
0
0.02
0.04
0.06
0.08
0.10
03757-010
Figure 5. X-Axis Zero g Bias Deviation from Ideal at 25°C
PERCENT OF POPULATION (%)
0
25
30
20
15
10
5
mg/°C
–0.80
–0.70
–0.60
–0.50
–0.40
–0.30
–0.20
–0.10
0
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
03757-011
Figure 6. X-Axis Zero g Bias Tempco
PERCENT OF POPULATION (%)
0
35
40
20
25
30
15
10
5
VOLTS/g
0.94
0.95
0.96
0.97
0.98
0.99
1.00
1.01
1.02
1.03
1.04
1.05
1.06
03757-012
Figure 7. X-Axis Sensitivity at 25°C
PERCENT OF POPULATION (%)
0
30
25
20
15
10
5
VOLTS
–0.10
–0.08
–0.06
–0.04
–0.02
0
0.02
0.04
0.06
0.08
0.10
03757-013
Figure 8. Y-Axis Zero g Bias Deviation from Ideal at 25°C
PERCENT OF POPULATION (%)
0
25
20
15
10
5
mg/°C
–0.80
–0.70
–0.60
–0.50
–0.40
–0.30
–0.20
–0.10
0
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
03757-014
Figure 9. Y-Axis Zero g Bias Tempco
PERCENT OF POPULATION (%)
0
35
40
20
25
30
15
10
5
VOLTS/g
0.94
0.95
0.96
0.97
0.98
0.99
1.00
1.01
1.02
1.03
1.04
1.05
1.06
03757-015
Figure 10. Y-Axis Sensitivity at 25°C
ADXL103/ADXL203
Rev. A | Page 7 of 12
TEMPERATURE (°C)
VOLTAGE (1V/g)
–50
2.40
2.60
2.58
2.56
2.54
2.52
2.50
2.48
2.46
2.44
2.42
–40
–30
–20
–10
0
10
20
30
50
40
60
70
80
90
100
110
120
130
03757-004
Figure 11. Zero g Bias vs. Temperature; Parts Soldered to PCB
X AXIS NOISE DENSITY (
μ
g
/
√
Hz)
PERCENT OF POPULATION (%)
0
40
35
30
25
20
15
10
5
45
50
15014013012011010090807060
03757-007
Figure 12. X-Axis Noise Density at 25°C
PERCENT SENSITIVITY (%)
PERCENT OF POPULATION (%)
–5.0
0
30
25
20
15
10
5
35
40
–4.0
–3.0
–2.0
–1.0
0
1.0
2.0
3.0
4.0
5.0
03757-005
Figure 13. Z vs. X Cross-Axis Sensitivity
TEMPERATURE (°C)
SENSITIVITY (V/
g
)
–50
0.97
1.00
0.99
0.98
1.02
1.01
1.03
–40
–30
–20
–10
0
10
20
30
50
40
60
70
80
90
100
110
120
130 03757-016
Figure 14. Sensitivity vs. Temperature; Parts Soldered to PCB
Y AXIS NOISE DENSITY (
μ
g
/
√
Hz)
PERCENT OF POPULATION (%)
0
40
35
30
25
20
15
10
5
45
50
15014013012011010090807060
03757-008
Figure 15. Y-Axis Noise Density at 25°C
PERCENT SENSITIVITY (%)
PERCENT OF POPULATION (%)
–5.0
0
30
25
20
15
10
5
35
40
–4.0
–3.0
–2.0
–1.0
0
1.0
2.0
3.0
4.0
5.0
03757-006
Figure 16. Z vs. Y Cross-Axis Sensitivity
ADXL103/ADXL203
Rev. A | Page 8 of 12
TEMPERATURE (°C)
CURRENT (mA)
0.3
0.8
0.7
0.6
0.5
0.4
0.9
150100500–50
V
S
= 5V
V
S
= 3V
03757-020
Figure 17. Supply Current vs. Temperature
PERCENT OF POPULATION (%)
0
45
20
25
30
35
40
15
10
5
VOLTS
0.40
0.45
0.50
0.55
0.65
0.60
0.70
0.75
0.80
0.85
0.90
0.95
1.00
03757-017
Figure 18. X-Axis Self-Test Response at 25°C
TEMPERATURE (°C)
VOLTAGE (1V/g)
–50
0.50
0.80
0.75
0.70
0.65
0.60
0.55
0.85
0.90
–40
–30
–20
–10
0
10
20
30
50
40
60
70
80
90
100
110
120
130 03757-003
Figure 19. Self-Test Response vs. Temperature
PERCENT OF POPULATION (%)
0
80
70
60
50
40
30
20
10
90
100
μ
A
3V
5V
200
300
400
500
600
700
800
900
1000
03757-018
Figure 20. Supply Current at 25°C
PERCENT OF POPULATION (%)
0
45
20
25
30
35
40
15
10
5
VOLTS
0.40
0.45
0.50
0.55
0.65
0.60
0.70
0.75
0.80
0.85
0.90
0.95
1.00
03757-019
Figure 21. Y-Axis Self-Test Response at 25°C
03757-009
Figure 22. Turn-On Time − CX, CY = 0.1 μF, Time Scale = 2 ms/div
ADXL103/ADXL203
Rev. A | Page 9 of 12
THEORY OF OPERATION
The ADXL103/ADXL203 are complete acceleration measure-
ment systems on a single, monolithic IC. The ADXL103 is a
single-axis accelerometer, and the ADXL203 is a dual-axis
accelerometer. Both parts contain a polysilicon surface-
micromachined sensor and signal conditioning circuitry to
implement an open-loop acceleration measurement architecture.
The output signals are analog voltages proportional to acceleration.
The ADXL103/ADXL203 are capable of measuring both positive
and negative accelerations to at least ±1.7 g. The accelerometer
can measure static acceleration forces such as gravity, allowing
it to be used as a tilt sensor.
The sensor is a surface-micromachined polysilicon structure
built on top of the silicon wafer. Polysilicon springs suspend the
structure over the surface of the wafer and provide a resistance
against acceleration forces. Deflection of the structure is measured
using a differential capacitor that consists of independent fixed
plates and plates attached to the moving mass. The fixed plates
are driven by 180° out-of-phase square waves. Acceleration deflects
the beam and unbalances the differential capacitor, resulting in
an output square wave whose amplitude is proportional to
acceleration. Phase-sensitive demodulation techniques are then
used to rectify the signal and determine the direction of the
acceleration.
The output of the demodulator is amplified and brought off-chip
through a 32 kΩ resistor. At this point, the user can set the
signal bandwidth of the device by adding a capacitor. This
filtering improves measurement resolution and helps prevent
aliasing.
PERFORMANCE
Rather than using additional temperature compensation circuitry,
innovative design techniques have been used to ensure that high
performance is built in. As a result, there is essentially no
quantization error or non-monotonic behavior, and temperature
hysteresis is very low (typically less than 10 mg over the −40°C
to +125°C temperature range).
Figure 11 shows the 0 g output performance of eight parts
(x and y axes) over a −40°C to +125°C temperature range.
Figure 14 demonstrates the typical sensitivity shift over
temperature for VS = 5 V. Sensitivity stability is optimized for
VS = 5 V but is still very good over the specified range; it is
typically better than ±1% over temperature at VS = 3 V.
EARTH'S SURFACE
TOP VIEW
(Not to Scale) PIN 8
X
OUT
= 2.5V
Y
OUT
= 1.5V
X
OUT
= 2.5V
Y
OUT
= 2.5V
PIN 8
X
OUT
= 2.5V
Y
OUT
= 3.5V
PIN 8
X
OUT
= 1.5V
Y
OUT
= 2.5V
PIN 8
X
OUT
= 3.5V
Y
OUT
= 2.5V
03757-021
Figure 23. Output Response vs. Orientation
ADXL103/ADXL203
Rev. A | Page 10 of 12
APPLICATIONS
POWER SUPPLY DECOUPLING
For most applications, a single 0.1 µF capacitor, CDC, adequately
decouples the accelerometer from noise on the power supply.
However in some cases, particularly where noise is present at
the 140 kHz internal clock frequency (or any harmonic thereof),
noise on the supply can cause interference on the ADXL103/
ADXL203 output. If additional decoupling is needed, a 100 Ω
(or smaller) resistor or ferrite beads can be inserted in the supply
line of the ADXL103/ADXL203. Additionally, a larger bulk
bypass capacitor (in the 1 µF to 22 µF range) can be added in
parallel to CDC.
SETTING THE BANDWIDTH USING CX AND CY
The ADXL103/ADXL203 has provisions for band limiting the
XOUT and YOUT pins. Capacitors must be added at these pins to
implement low-pass filtering for antialiasing and noise reduction.
The equation for the 3 dB bandwidth is
F–3 dB = 1/(2π(32 kΩ) × C(X, Y))
or more simply,
F–3 dB = 5 µF/C(X, Y)
The tolerance of the internal resistor (RFILT) can vary typically as
much as ±25% of its nominal value (32 kΩ); thus, the bandwidth
varies accordingly. A minimum capacitance of 2000 pF for CX and
CY is required in all cases.
Table 6. Filter Capacitor Selection, CX and CY
Bandwidth (Hz) Capacitor (μF)
1 4.7
10 0.47
50 0.10
100 0.05
200 0.027
500 0.01
SELF TEST
The ST pin controls the self-test feature. When this pin is set to
VS, an electrostatic force is exerted on the beam of the acceler-
ometer. The resulting movement of the beam allows the user to
test if the accelerometer is functional. The typical change in
output is 750 mg (corresponding to 750 mV). This pin can be
left open-circuit or connected to common in normal use.
The ST pin should never be exposed to voltage greater than
VS + 0.3 V. If the system design is such that this condition
cannot be guaranteed (that is, multiple supply voltages are
present), a low VF clamping diode between ST and VS is
recommended.
DESIGN TRADE-OFFS FOR SELECTING FILTER
CHARACTERISTICS: THE NOISE/BW TRADE-OFF
The accelerometer bandwidth selected ultimately determines
the measurement resolution (smallest detectable acceleration).
Filtering can be used to lower the noise floor, improving the
resolution of the accelerometer. Resolution is dependent on the
analog filter bandwidth at XOUT and YOUT.
The output of the ADXL103/ADXL203 has a typical bandwidth
of 2.5 kHz. The user must filter the signal at this point to limit
aliasing errors. The analog bandwidth must be no more than
half the analog-to-digital sampling frequency to minimize
aliasing. The analog bandwidth can be further decreased to
reduce noise and improve resolution.
The ADXL103/ADXL203 noise has the characteristics of white
Gaussian noise, which contributes equally at all frequencies and
is described in terms of µg/√Hz (that is, the noise is proportional to
the square root of the accelerometer bandwidth). The user should
limit bandwidth to the lowest frequency needed by the application
to maximize the resolution and dynamic range of the
accelerometer.
With the single pole roll-off characteristic, the typical noise of
the ADXL103/ADXL203 is determined by
)6.1BW()Hz/µ110(rmsNoise ××= g
At 100 Hz, the noise is
gg m4.1)6.1100()Hz/µ110(rmsNoise =××=
Often, the peak value of the noise is desired. Peak-to-peak noise
can only be estimated by statistical methods. Table 7 is useful
for estimating the probabilities of exceeding various peak
values, given the rms value.
Table 7. Estimation of Peak-to-Peak Noise
Peak-to-Peak Value
% of Time That Noise Exceeds
Nominal Peak-to-Peak Value
2 × rms 32
4 × rms 4.6
6 × rms 0.27
8 × rms 0.006
ADXL103/ADXL203
Rev. A | Page 11 of 12
Peak-to-peak noise values give the best estimate of the uncertainty
in a single measurement; peak-to-peak noise is estimated by
6 × rms. Table 8 gives the typical noise output of the ADXL103/
ADXL203 for various CX and CY values.
Table 8. Filter Capacitor Selection (CX, CY)
Bandwidth (Hz)
CX, CY
(μF)
RMS Noise
(mg)
Peak-to-Peak Noise
Estimate (mg)
10 0.47 0.4 2.6
50 0.1 1.0 6
100 0.047 1.4 8.4
500 0.01 3.1 18.7
USING THE ADXL103/ADXL203 WITH OPERATING
VOLTAGES OTHER THAN 5 V
The ADXL103/ADXL203 is tested and specified at VS = 5 V;
however, it can be powered with VS as low as 3 V or as high as
6 V. Some performance parameters change as the supply voltage
is varied.
The ADXL103/ADXL203 output is ratiometric, so the output
sensitivity (or scale factor) varies proportionally to supply
voltage. At VS = 3 V the output sensitivity is typically 560 mV/g.
The zero g bias output is also ratiometric, so the zero g output is
nominally equal to VS/2 at all supply voltages.
The output noise is not ratiometric but is absolute in volts;
therefore, the noise density decreases as the supply voltage
increases. This is because the scale factor (mV/g) increases
while the noise voltage remains constant. At VS = 3 V, the noise
density is typically 190 µg/√Hz.
Self-test response in g is roughly proportional to the square of
the supply voltage. However, when ratiometricity of sensitivity
is factored in with supply voltage, self-test response in volts is
roughly proportional to the cube of the supply voltage. So at
VS = 3 V, the self-test response is approximately equivalent to
150 mV or equivalent to 270 mg (typical).
The supply current decreases as the supply voltage decreases.
Typical current consumption at VDD = 3 V is 450 µA.
USING THE ADXL203 AS A DUAL-AXIS TILT
SENSOR
One of the most popular applications of the ADXL203 is tilt
measurement. An accelerometer uses the force of gravity as an
input vector to determine the orientation of an object in space.
An accelerometer is most sensitive to tilt when its sensitive axis
is perpendicular to the force of gravity, that is, parallel to the
earth’s surface. At this orientation, its sensitivity to changes in
tilt is highest. When the accelerometer is oriented on axis to
gravity, that is, near its +1 g or –1 g reading, the change in
output acceleration per degree of tilt is negligible. When the
accelerometer is perpendicular to gravity, its output changes
nearly 17.5 mg per degree of tilt. At 45°, its output changes at
only 12.2 mg per degree, and resolution declines.
Dual-Axis Tilt Sensor: Converting Acceleration to Tilt
When the accelerometer is oriented so both its x axis and y axis
are parallel to the earth’s surface, it can be used as a 2-axis tilt
sensor with a roll axis and a pitch axis. Once the output signal
from the accelerometer has been converted to an acceleration
that varies between –1 g and +1 g, the output tilt in degrees is
calculated as follows:
PITCH = ASIN(AX/1 g)
ROLL = ASIN(AY/1 g)
Be sure to account for overranges. It is possible for the
accelerometers to output a signal greater than ±1 g due to
vibration, shock, or other accelerations.
ADXL103/ADXL203
Rev. A | Page 12 of 12
OUTLINE DIMENSIONS
BOTTOM VIEW
1
3
5
7
0.64
1.90
2.50
2.50
0.38 DIAMETER
0.50 DIAMETER
1.27
1.27
1.27
4.50
SQ
5.00
SQ
TOP VIEW
R 0.38 0.20
1.78
R 0.20
Figure 24. 8-Terminal Ceramic Leadless Chip Carrier [LCC]
(E-8)
Dimensions shown in millimeters
ORDERING GUIDE
Model
Number
of Axes Specified Voltage (V) Temperature Range Package Description
Package
Option
ADXL103CE11 5 –40°C to +125°C 8-Lead Ceramic Leadless Chip Carrier E-8
ADXL103CE–REEL11 5 –40°C to +125°C 8-Lead Ceramic Leadless Chip Carrier E-8
ADXL203CE12 5 –40°C to +125°C 8-Lead Ceramic Leadless Chip Carrier E-8
ADXL203CE–REEL12 5 –40°C to +125°C 8-Lead Ceramic Leadless Chip Carrier E-8
ADXL203EB Evaluation Board
1 Lead finish. Gold over nickel over tungsten.
©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D03757-0-3/06(A)
