Page 1
Small, Low Power, 3-Axis ±3 g
www.BDTIC.com/ADI
Preliminary Technical Data
FEATURES
3-axis sensing
Small, low-profile package
4 mm × 4 mm × 1.45 mm LFCSP
Low power - 350 μA (typical)
Single-supply operation
1.8 V to 3.6 V
10,000 g shock survival
Excellent temperature stability
BW adjustment with a single capacitor per axis
RoHS/WEEE lead-free compliant
APPLICATIONS
Cost-sensitive, low power, motion- and tilt-sensing
applications
Mobile devices
Gaming systems
Disk drive protection
Image stabilization
Sports and health devices
Accelerometer
ADXL335
GENERAL DESCRIPTION
The ADXL335 is a small, thin, low power, complete 3-axis
accelerometer with signal conditioned voltage outputs. The
product measures acceleration with a minimum full-scale range
of ±3 g. It can measure the static acceleration of gravity in tiltsensing applications, as well as dynamic acceleration resulting
from motion, shock, or vibration.
The user selects the bandwidth of the accelerometer using the
C
, CY, and CZ capacitors at the X
X
Bandwidths can be selected to suit the application, with a
range of 0.5 Hz to 1600 Hz for X and Y axes, and a range of
0.5 Hz to 550 Hz for the Z axis.
The ADXL335 is available in a small, low profile, 4 mm × 4 mm
× 1.45 mm, 16-lead, plastic lead frame chip scale package
(LFCSP_LQ).
OUT
, Y
OUT
, and Z
OUT
pins.
+3V
+3V
Vs
Vs
3-Axis
3-Axis
C
C
DC
DC
Sensor
Sensor
COM ST
COM ST
FUNCTIONAL BLOCK DIAGRAM
ADXL335
ADXL335
AC
AC
Amp
Amp
Figure 1.
Demod
Demod
Output
Output
Amp
Amp
Output
Output
Amp
Amp
Output
Output
Amp
Amp
~32kΩ
~32kΩ
~32kΩ
~32kΩ
~32kΩ
~32kΩ
X
X
OUT
OUT
C
C
X
X
Y
Y
OUT
OUT
C
C
Y
Y
Z
Z
OUT
OUT
C
C
Z
Z
Rev. PrA
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2008 Analog Devices, Inc. All rights reserved.
Page 2
ADXL335 Preliminary Technical Data
www.BDTIC.com/ADI
TABLE OF CONTENTS
Features .............................................................................................. 1
Performance ...................................................................................6
Applications ....................................................................................... 1
General Description ......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
Absolute Maximum Ratings ............................................................ 4
ESD Caution .................................................................................. 4
Pin Configuration and Function Descriptions ............................. 5
Theory of Operation ........................................................................ 6
Mechanical Sensor ........................................................................ 6
REVISION HISTORY
Applications ........................................................................................7
Power Supply Decoupling ............................................................7
Setting the Bandwidth Using CX, CY, and C
Self Test ...........................................................................................7
Design Trade-Offs for Selecting Filter Characteristics: The
Noise/BW Trade-Off .....................................................................7
Use with Operating Voltages Other than 3 V ................................7
Axes of Acceleration Sensitivity ..................................................8
Outline Dimensions ..........................................................................9
Ordering Guide .............................................................................9
.............................7
Z
Rev. PrA | Page 2 of 11
Page 3
Preliminary Technical Data ADXL335
www.BDTIC.com/ADI
SPECIFICATIONS
TA = 25°C, VS = 3 V, CX = CY = CZ = 0.1 µF, acceleration = 0 g, unless otherwise noted. All minimum and maximum specifications are
guaranteed. Typical specifications are not guaranteed.
Table 1.
Parameter Conditions Min Typ Max Unit
SENSOR INPUT Each axis
Measurement Range ±3 ±3.6
Nonlinearity % of full scale ±0.3 %
Package Alignment Error ±1 Degrees
Interaxis Alignment Error ±0.1 Degrees
Cross Axis Sensitivity1 ±1 %
SENSITIVITY (RATIOMETRIC)2 Each axis
Sensitivity at X
Sensitivity Change Due to Temperature3 V
OUT
, Y
, Z
V
OUT
OUT
= 3 V 270 300 330 mV/g
S
= 3 V ±0.01 %/°C
S
ZERO g BIAS LEVEL (RATIOMETRIC)
0 g Voltage at X
0 g Voltage at Z
, Y
V
OUT
OUT
V
OUT
= 3 V 1.35 1.5 1.65 V
S
= 3 V 1.2 1.5 1.8 V
S
0 g Offset vs. Temperature ±1 mg/°C
NOISE PERFORMANCE
Noise Density X
Noise Density Z
, Y
150 µg/√Hz rms
OUT
OUT
300 µg/√Hz rms
OUT
FREQUENCY RESPONSE4
Bandwidth X
Bandwidth Z
R
Tolerance 32 ± 15% kΩ
FILT
5
, Y
OUT
OUT
No external filter 1600 Hz
OUT
5
No external filter 550 Hz
Sensor Resonant Frequency 5.5 kHz
SELF TEST6
Logic Input Low +0.6 V
Logic Input High +2.4 V
ST Actuation Current +60 A
Output Change at X
Output Change at Y
Output Change at Z
Self test 0 to 1 −300 mV
OUT
Self test 0 to 1 +300 mV
OUT
Self test 0 to 1 +550 mV
OUT
OUTPUT AMPLIFIER
Output Swing Low No load 0.1 V
Output Swing High No load 2.8 V
POWER SUPPLY
Operating Voltage Range 1.8 3.6 V
Supply Current VS = 3 V 350 A
Turn-On Time7 No external filter 1 ms
TEMPERATURE
Operating Temperature Range −40 +85 °C
1
Defined as coupling between any two axes.
2
Sensitivity is essentially ratiometric to VS.
3
Defined as the output change from ambient-to-maximum temperature or ambient-to-minimum temperature.
4
Actual frequency response controlled by user-supplied external filter capacitors (CX, CY, CZ).
5
Bandwidth with external capacitors = 1/(2 × π × 32 kΩ × C). For CX, CY = 0.003 µF, bandwidth = 1.6 kHz. For CZ = 0.01 µF, bandwidth = 500 Hz. For CX, CY, CZ = 10 µF,
bandwidth = 0.5 Hz.
6
Self-test response changes cubically with VS.
7
Turn-on time is dependent on CX, CY, CZ and is approximately 160 × CX or CY or CZ + 1 ms, where CX, CY, CZ are in µF.
g
Rev. PrA | Page 3 of 11
Page 4
ADXL335 Preliminary Technical Data
www.BDTIC.com/ADI
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
Acceleration (Any Axis, Unpowered) 10,000 g
Acceleration (Any Axis, Powered) 10,000 g
VS −0.3 V to +3.6 V
All Other Pins (COM − 0.3 V) to (VS + 0.3 V)
Output Short-Circuit Duration
Indefinite
(Any Pin to Common)
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.
Temperature Range (Powered) −55°C to +125°C
Temperature Range (Storage) −65°C to +150°C
CRITICAL Z ONE
t
L
T
TO T
L
P
05677-002
TEMPERATURE
t
T
P
T
L
T
SMAX
T
SMIN
PREHEAT
t
25°C TO PEA K
Figure 2. Recommended Soldering Profile
RAMP-UP
t
S
P
RAMP-DOWN
TIME
Table 3. Recommended Soldering Profile
Profile Feature Sn63/Pb37 Pb-Free
Average Ramp Rate (TL to TP) 3°C/s max 3°C/s max
Preheat
Minimum Temperature (T
Maximum Temperature (T
Time (T
T
to TL
SMAX
SMIN
to T
), tS 60 s to 120 s 60 s to 180 s
SMAX
) 100°C 150°C
SMIN
) 150°C 200°C
SMAX
Ramp-Up Rate 3°C/s max 3°C/s max
Time Maintained Above Liquidous (TL)
Liquidous Temperature (TL) 183°C 217°C
Time (tL) 60 s to 150 s 60 s to 150 s
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 s to 30 s 20 s to 40 s
Ramp-Down Rate 6°C/s max 6°C/s max
Time 25°C to Peak Temperature 6 minutes max 8 minutes max
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.
Rev. PrA | Page 4 of 11
Page 5
Preliminary Technical Data ADXL335
C
www.BDTIC.com/ADI
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
0.50
MAX
4
0.65 0.325
0.65
1.95
0.325
NC
NC
ST
ST
NC
NC
NC
Vs
NC
NC
Vs
1
1
2
2
3
3
ADXL335
ADXL335
TOP VIEW
TOP VIEW
(Not to Scale)
(Not to Scale)
+Z
+Z
NC
13141516
13141516
+Y
+Y
NC
NC
12
12
11
11
10
10
X
X
NC
NC
Y
Y
OUT
OUT
OUT
OUT
0.35
MAX
4
NC
NC
4
4
5678
5678
+X
+X
NC
NC
NC
COM
COM
NC
Figure 3. Pin Configuration
9
9
NC
NC
OUT
OUT
Z
Z
ENTER PAD IS NO T
INTERNALLY CONNECTED
BUT SHOULD BE SOLDERED
FOR MECHANICAL INTEGRITY
Figure 4. Recommended PCB Layout
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 NC No Connect (or optionally ground)
2 ST Self Test
3 NC No Connect1
4 NC No Connect1
5 COM Common
6 NC No Connect1
7 NC No Connect1
8 Z
Z Channel Output
OUT
9 NC No Connect (or optionally ground)
10 Y
Y Channel Output
OUT
11 NC No Connect1
12 X
X Channel Output
OUT
13 NC No Connect1
14 NC No Connect1
15 VS Supply Voltage (1.8 V to 3.6 V)
16 NC No Connect1
1
NC pins are not internally connected and can be tied to Vs or Common unless otherwise noted.
1.95
DIMENSIONS SHOWN IN MILLIMETERS
05677-032
Rev. PrA | Page 5 of 11
Page 6
ADXL335 Preliminary Technical Data
www.BDTIC.com/ADI
THEORY OF OPERATION
The ADXL335 is a complete 3-axis acceleration measurement
system. The ADXL335 has a measurement range of ±3 g
minimum. It contains a polysilicon surface micromachined
sensor and signal conditioning circuitry to implement an openloop acceleration measurement architecture. The output signals
are analog voltages that are proportional to acceleration. The
accelerometer can measure the static acceleration of gravity in
tilt sensing applications as well as dynamic acceleration
resulting from motion, shock, or vibration.
The sensor is a polysilicon surface micromachined structure
built on top of a 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 moving mass and unbalances the differential
capacitor resulting in a sensor output whose amplitude is
proportional to acceleration. Phase-sensitive demodulation
techniques are then used to determine the magnitude and
direction of the acceleration.
MECHANICAL SENSOR
The ADXL335 uses a single structure for sensing the X, Y, and
Z axes. As a result, the three axes sense directions are highly
orthogonal with little cross axis sensitivity. Mechanical misalignment of the sensor die to the package is the chief source
of cross axis sensitivity. Mechanical misalignment can, of
course, be calibrated out at the system level.
PERFORMANCE
Rather than using additional temperature compensation
circuitry, innovative design techniques ensure high
performance is built-in to the ADXL335. As a result, there is
neither quantization error nor nonmonotonic behavior, and
temperature hysteresis is very low (typically less than 3 mg over
the −25°C to +70°C temperature range).
The demodulator output is amplified and brought off-chip
through a 32 kΩ resistor. The user then sets the signal bandwidth of the device by adding a capacitor. This filtering improves
measurement resolution and helps prevent aliasing.
Rev. PrA | Page 6 of 11
Page 7
Preliminary Technical Data ADXL335
www.BDTIC.com/ADI
APPLICATIONS
POWER SUPPLY DECOUPLING
For most applications, a single 0.1 µF capacitor, CDC, placed
close to the ADXL335 supply pins adequately decouples the
accelerometer from noise on the power supply. However, in
applications where noise is present at the 50 kHz internal clock
frequency (or any harmonic thereof), additional care in power
supply bypassing is required as this noise can cause errors in
acceleration measurement. If additional decoupling is needed,
a 100 Ω (or smaller) resistor or ferrite bead can be inserted in
the supply line. Additionally, a larger bulk bypass capacitor
(1 µF or greater) can be added in parallel to C
. Ensure that
DC
the connection from the ADXL335 ground to the power supply
ground is low impedance because noise transmitted through
ground has a similar effect as noise transmitted through V
.
S
SETTING THE BANDWIDTH USING CX, CY, AND CZ
The ADXL335 has provisions for band limiting the X
and Z
pins. Capacitors must be added at these pins to
OUT
implement low-pass filtering for antialiasing and noise
reduction. The equation for the 3 dB bandwidth is
F
= 1/(2π(32 kΩ) × C
−3 dB
(X, Y, Z )
)
or more simply
= 5 F/C
F
–3 dB
The tolerance of the internal resistor (R
(X, Y, Z )
) typically varies as
FILT
much as ±15% of its nominal value (32 kΩ), and the bandwidth
varies accordingly. A minimum capacitance of 0.0047 F for C
C
, and CZ is recommended in all cases.
Y
Table 5. Filter Capacitor Selection, C
Bandwidth (Hz) Capacitor (μF)
1 4.7
10 0.47
50 0.10
100 0.05
200 0.027
500 0.01
, CY, and CZ
X
OUT
, Y
OUT
,
,
X
SELF TEST
The ST pin controls the self test feature. When this pin is set to
, an electrostatic force is exerted on the accelerometer beam.
V
S
The resulting movement of the beam allows the user to test if
the accelerometer is functional. The typical change in output is
−500 mg (corresponding to −150 mV) in the X-axis, 500 mg (or
150 mV) on the Y-axis, and −200 mg (or −60 mV) on the Z-axis.
This ST pin may be left open circuit or connected to common
(COM) in normal use.
Never expose the ST pin to voltages greater than V
this cannot be guaranteed due to the system design (for
instance, if there are multiple supply voltages), then a low V
clamping diode between ST and V
is recommended.
S
DESIGN TRADE-OFFS FOR SELECTING FILTER
CHARACTERISTICS: THE NOISE/BW TRADE-OFF
The selected accelerometer bandwidth ultimately determines
the measurement resolution (smallest detectable acceleration).
Filtering can be used to lower the noise floor to improve the
resolution of the accelerometer. Resolution is dependent on the
analog filter bandwidth at X
OUT
, Y
OUT
, and Z
The output of the ADXL335 has a typical bandwidth of greater
than 500 Hz. 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 ADXL335 noise has the characteristics of white Gaussian
noise, which contributes equally at all frequencies and is
described in terms of g/√Hz (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 ADXL335 is determined by
Often, the peak value of the noise is desired. Peak-to-peak noise
can only be estimated by statistical methods. Table 6 is useful
for estimating the probabilities of exceeding various peak
values, given the rms value.
Table 6. Estimation of Peak-to-Peak Noise
% of Time that Noise Exceeds
Peak-to-Peak Value
2 × rms 32
4 × rms 4.6
6 × rms 0.27
8 × rms 0.006
Nominal Peak-to-Peak Value
USE WITH OPERATING VOLTAGES OTHER THAN 3 V
The ADXL335 is tested and specified at VS = 3 V; however, it
can be powered with V
that some performance parameters change as the supply voltage
is varied.
as low as 1.8 V or as high as 3.6 V. Note
S
OUT
.
)1.6( ××= BWDensityNoiseNoiserms
+ 0.3 V. If
S
F
Rev. PrA | Page 7 of 11
Page 8
ADXL335 Preliminary Technical Data
A
X
Y
Z
www.BDTIC.com/ADI
At V
= 2 V, the self test response is approximately −60 mV for
The ADXL335 output is ratiometric, therefore, the output
sensitivity (or scale factor) varies proportionally to the
supply voltage. At V
typically 360 mV/g. At V
= 3.6 V, the output sensitivity is
S
= 2 V, the output sensitivity is
S
typically 195 mV/g.
The zero g bias output is also ratiometric, so the zero g output is
nominally equal to V
/2 at all supply voltages.
S
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 V
= 3.6 V, the
S
X- and Y-axis noise density is typically 120 µg/√Hz, while at
V
= 2 V, the X- and Y-axis noise density is typically 270 g/√Hz.
S
S
the X-axis, +60 mV for the Y-axis, and −25 mV for the Z-axis.
The supply current decreases as the supply voltage decreases.
Typical current consumption at V
typical current consumption at V
= 3.6 V is 375 µA, and
S
= 2 V is 200 µA.
S
AXES OF ACCELERATION SENSITIVITY
Z
A
Y
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, the self test response in volts
is roughly proportional to the cube of the supply voltage. For
example, at V
= 3.6 V, the self test response for the ADXL335 is
S
approximately −275 mV for the X-axis, +275 mV for the Y-axis,
and −100 mV for the Z-axis.
X
= –1g
OUT
= 0g
Y
OUT
= 0g
Z
OUT
TOP
= 0g
OUT
OUT
OUT
= 1g
= 0g
TOP
TOP
X
= 1g
OUT
Y
= 0g
OUT
= 0g
Z
OUT
TOP
TO
P
Figure 5. Axes of Acceleration Sensitivity, Corresponding Output Voltage
Increases When Accelerated Along the Sensitive Axis
GRAVITY
X
= 0g
OUT
= –1g
Y
OUT
= 0g
Z
OUT
T
O
P
A
X
05677-030
Figure 6. Output Response vs. Orientation to Gravity
Rev. PrA | Page 8 of 11
= 0g
X
OUT
= 0g
Y
OUT
= 1g
Z
OUT
X
= 0g
OUT
= 0g
Y
OUT
= –1g
Z
OUT
05677-031
Page 9
Preliminary Technical Data ADXL335
C
www.BDTIC.com/ADI
OUTLINE DIMENSIONS
INDI
PIN 1
ATOR
1.50
1.45
1.40
SEATING
PLANE
TOP
VIEW
4.15
4.00 SQ
3.85
0.05 MAX
0.02 NOM
0.35
COPLANARITY
0.30
0.25
*
STACKED DIE WITH GLASS S EAL.
0.05
0.20 MIN
0.65 BSC
0.55
0.50
0.45
12
9
0.20 MIN
13
BOTTO M
VIEW
8
Figure 7. 16-Lead Lead Frame Chip Scale Package [LFCSP_LQ]
4 mm × 4 mm Body, 1.45mm Thick Quad
(CP-16-5a*)
Dimensions shown in millimeters
ORDERING GUIDE
Model Measurement Range Specified Voltage Temperature Range Package Description Package Option
ADXL335BCPZ1 ±3 g 3 V −40°C to +85°C 16-Lead LFCSP_LQ CP-16-5a
ADXL335BCPZ–RL1 ±3 g 3 V −40°C to +85°C 16-Lead LFCSP_LQ CP-16-5a
ADXL335BCPZ–RL71 ±3 g 3 V −40°C to +85°C 16-Lead LFCSP_LQ CP-16-5a
EVAL-ADXL335Z1 Evaluation Board
1
Z = Pb-free part.
16
5
1
4
1.95 BSC
PIN 1
INDICATOR
2.43
1.75 SQ
1.08
072606-A
Rev. PrA | Page 9 of 11
Page 10
ADXL335 Preliminary Technical Data
www.BDTIC.com/ADI
NOTES
Rev. PrA | Page 10 of 11
Page 11
Preliminary Technical Data ADXL335
www.BDTIC.com/ADI
NOTES
©2008 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
PR07808-0-9/08(PrA)
Rev. PrA | Page 11 of 11
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