EVAL-ADXL377Z [ADI]
Small, Low Power, 3-Axis 200 g Accelerometer; 小尺寸，低功耗， 3轴200克加速度计
| 型号： | EVAL-ADXL377Z |
| 厂家： | 
ADI |
| 描述： | Small, Low Power, 3-Axis 200 g Accelerometer |
| 文件： | 总12页 (文件大小：261K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Small, Low Power, 3-Axis
200 g Accelerometer
Data Sheet
ADXL377
FEATURES
GENERAL DESCRIPTION
3-axis sensing
Small, low profile package
3 mm × 3 mm × 1.45 mm LFCSP
Low power: 300 µA (typical)
The ADXL377 is a small, thin, low power, complete 3-axis
accelerometer with signal conditioned voltage outputs. The
ADXL377 measures acceleration resulting from motion, shock,
or vibration with a typical full-scale range of 200 g.
Single-supply operation: 1.8 V to 3.6 V
10,000 g shock survival
Excellent temperature stability
Bandwidth adjustment with a single capacitor per axis
RoHS/WEEE and lead-free compliant
The user selects the bandwidth of the accelerometer using
the CX, CY, and CZ capacitors at the XOUT, YOUT, and ZOUT pins.
Bandwidths can be selected to suit the application, with a range
of 0.5 Hz to 1300 Hz for the x-axis and y-axis and a range of
0.5 Hz to 1000 Hz for the z-axis.
APPLICATIONS
The ADXL377 is available in a small, low profile, 3 mm × 3 mm ×
1.45 mm, 16-lead lead frame chip scale package (LFCSP_LQ).
Concussion and head trauma detection
High force event detection
FUNCTIONAL BLOCK DIAGRAM
+3V
V
S
ADXL377
X
Y
Z
32kΩ
32kΩ
32kΩ
OUT
OUTPUT
AMPLIFIERS
AC
AMPLIFIER
C
C
C
X
Y
Z
C
OUT
DC
DEMODULATOR
3-AXIS
SENSOR
OUT
GND
ST
Figure 1.
Rev. 0
Document Feedback
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rightsof third parties that may result fromits 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 andregisteredtrademarks 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
Technical Support
©2012 Analog Devices, Inc. All rights reserved.
www.analog.com
ADXL377
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Performance...................................................................................8
Applications Information .................................................................9
Power Supply Decoupling ............................................................9
Setting the Bandwidth Using CX, CY, and CZ.............................9
Self-Test ..........................................................................................9
Selecting Filter Characteristics: Noise/Bandwidth Trade-Off....9
Axes of Acceleration Sensitivity ............................................... 10
Layout and Design Recommendations ................................... 11
Outline Dimensions....................................................................... 12
Ordering Guide .......................................................................... 12
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
Typical Performance Characteristics ............................................. 6
Theory of Operation ........................................................................ 8
Mechanical Sensor........................................................................ 8
REVISION HISTORY
9/12—Revision 0: Initial Version
Rev. 0 | Page 2 of 12
Data Sheet
ADXL377
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
Test Conditions/Comments
Min
Typ
200
Max
Unit
SENSOR INPUT
Measurement Range
Each axis
g
Nonlinearity
% of full scale up to 180 g
0.ꢀ
1.ꢁ
%
%
Cross-Axis Sensitivity1
SENSITIVITY, RATIOMETRIC2
Sensitivity at XOUT, YOUT, and ZOUT
Sensitivity Change Due to Temperature3
ZERO g BIAS LEVEL, RATIOMETRIC
Zero g Voltage
Each axis
VS = 3 V
VS = 3 V
ꢀ.8
1.ꢁ
6.ꢀ
0.02
7.2
1.6
mV/g
%/°C
VS = 3 V, TA = 2ꢀ°C
1.ꢀ
V
Zero g Offset vs. Temperature
X-Axis and Y-Axis
Z-Axis
12
30
mg/°C
mg/°C
NOISE PERFORMANCE
Noise Density
XOUT and YOUT
ZOUT
2.7
ꢁ.3
mg/√Hz
mg/√Hz
FREQUENCY RESPONSEꢁ
Bandwidthꢀ
No external filter
XOUT and YOUT
1300
Hz
ZOUT
1000
Hz
RFILT Tolerance
Sensor Resonant Frequency
SELF-TEST6
32 1ꢀ%
16.ꢀ
kΩ
kHz
Logic Input Low
0.6
2.ꢁ
60
V
V
μA
Logic Input High
ST Actuation Current
Output Change
At XOUT
At YOUT
Self-test, 0 to 1
No load
−6.ꢀ
6.ꢀ
11.ꢀ
mV
mV
mV
At ZOUT
OUTPUT AMPLIFIER
Output Swing Low
Output Swing High
POWER SUPPLY
Operating Voltage Range7
Supply Current
Turn-On Time8
0.1
2.8
V
V
1.8
3.0
300
1
3.6
V
VS = 3 V
No external filter
μA
ms
°C
OPERATING TEMPERATURE RANGE
−ꢁ0
+8ꢀ
1 Defined as coupling between any two axes.
2 Sensitivity is essentially ratiometric to VS.
3 Defined as the output change from ambient temperature to maximum temperature or from ambient temperature to minimum temperature.
ꢁ Actual frequency response controlled by user-supplied external filter capacitors (CX, CY, and CZ).
ꢀ Bandwidth with external capacitors = 1/(2π × 32 kΩ × Cx).
6 Self-test response changes cubically with VS.
7 Tested at 3.0 V and guaranteed by design only (not tested) to work over the full voltage range from 1.8 V to 3.6 V.
8 Turn-on time is dependent on CX, CY, and CZ and is approximately 160 × (CX or CY or CZ) + 1, where CX, CY, and CZ are in μF and the resulting turn-on time is in ms.
Rev. 0 | Page 3 of 12
ADXL377
Data Sheet
ABSOLUTE MAXIMUM RATINGS
Table 2.
ESD CAUTION
Parameter
Acceleration (Any Axis)
Unpowered
Powered
Rating
10,000 g
10,000 g
VS
−0.3 V to +3.6 V
(GND − 0.3 V) to (VS + 0.3 V)
Indefinite
All Other Pins
Output Short-Circuit Duration
(Any Pin to Ground)
Operating Temperature Range
Storage Temperature Range
−55°C to +125°C
−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.
Rev. 0 | Page 4 of 12
Data Sheet
ADXL377
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
16
15
14
13
ADXL377
1
2
3
4
12
RES
ST
NC
TOP VIEW
(Not to Scale)
11
10
NC
NC
+Y
RES
+Z
+X
9
Y
NC
OUT
5
6
7
8
NOTES
1. NC = NO CONNECT.
2. THE EXPOSED PAD IS NOT INTERNALLY
CONNECTED, BUT SHOULD BE SOLDERED
FOR MECHANICAL INTEGRITY.
Figure 2. Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
1, 3
2
Mnemonic
Description
RES
ST
Reserved. This pin must be connected to GND or left open.
Self-Test.
4
YOUT
Y Channel Output.
5
XOUT
GND
NC
VS
ZOUT
X Channel Output.
6, 7
8 to 13
14, 15
16
Must be connected to ground.
No Connect. Not internally connected.
Supply Voltage. 3.0 V typical.
Z Channel Output.
EPAD
Exposed Pad. The exposed pad is not internally connected, but should be soldered for mechanical integrity.
Rev. 0 | Page 5 of 12
ADXL377
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
N > 250 for all typical performance figures, unless otherwise noted. N is the number of parts tested and used to produce the histograms.
1.525
1.520
1.515
1.510
1.505
1.500
1.495
1.490
1.485
1.480
35
30
25
20
15
10
5
0
–60
–40
–20
0
20
40
60
80
100
100
100
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
Figure 3. X-Axis Zero g Output Voltage at 25°C, VS = 3 V
Figure 6. X-Axis Zero g Offset vs. Temperature, VS = 3 V
(14 Parts Soldered to PCB)
30
1.525
1.520
1.515
1.510
1.505
1.500
1.495
1.490
1.485
1.480
25
20
15
10
5
0
–60
–40
–20
0
20
40
60
80
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
Figure 4. Y-Axis Zero g Output Voltage at 25°C, VS = 3 V
Figure 7. Y-Axis Zero g Offset vs. Temperature, VS = 3 V
(14 Parts Soldered to PCB)
90
1.525
1.520
1.515
1.510
1.505
1.500
1.495
1.490
1.485
1.480
80
70
60
50
40
30
20
10
0
–60
–40
–20
0
20
40
60
80
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
Figure 5. Z-Axis One g Output Voltage at 25°C, VS = 3 V
Figure 8. Z-Axis Zero g Offset vs. Temperature, VS = 3 V
(14 Parts Soldered to PCB)
Rev. 0 | Page 6 of 12
Data Sheet
ADXL377
25
20
15
10
5
250
200
150
100
50
X-AXIS
Y-AXIS
Z-AXIS
0
0
0
50
100
150
200
REFERENCE ACCELERATION (g)
SENSITIVITY (mV/g)
Figure 9. X-Axis Sensitivity at 25°C, VS = 3 V
Figure 12. Typical Output Linearity over the Dynamic Range
30
25
20
15
10
5
10
X-AXIS, Y-AXIS RESPONSE
Z-AXIS RESPONSE
0
1
10
100
FREQUENCY (Hz)
1k
10k
SENSITIVITY (mV/g)
Figure 10. Y-Axis Sensitivity at 25°C, VS = 3 V
Figure 13. Typical Frequency Response
16
14
12
10
8
6
4
2
0
SENSITIVITY (mV/g)
Figure 11. Z-Axis Sensitivity at 25°C, VS = 3 V
Rev. 0 | Page 7 of 12
ADXL377
Data Sheet
THEORY OF OPERATION
The ADXL377 is a complete 3-axis acceleration measurement
system with a typical measurement range of 200 g. The ADXL377
contains a polysilicon, surface-micromachined sensor and signal
conditioning circuitry to implement an open-loop acceleration
measurement architecture. The output signals are analog voltages
that are proportional to acceleration. The accelerometer can mea-
sure the static acceleration of gravity in tilt-sensing applications,
as well as dynamic acceleration resulting from motion, shock,
or vibration.
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.
MECHANICAL SENSOR
The ADXL377 uses a single structure for sensing the accelera-
tion in the x-axis, y-axis, and z-axis. As a result, the three sense
directions are highly orthogonal with little cross-axis sensitivity.
Mechanical misalignment of the sensor die to the package or
misalignment of the package to the PCB is the chief source of
cross-axis sensitivity. Mechanical misalignment can be calibrated
at the system level.
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 resistance
against acceleration forces. Deflection of the structure is mea-
sured 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.
PERFORMANCE
Rather than using additional temperature compensation circuitry,
the ADXL377 uses innovative design techniques to ensure high
performance. As a result, there is neither quantization error nor
nonmonotonic behavior, and temperature hysteresis is very low.
Rev. 0 | Page 8 of 12
Data Sheet
ADXL377
APPLICATIONS INFORMATION
Never expose the ST pin to voltages greater than VS + 0.3 V. If
the system design is such that this condition cannot be guaran-
teed (for example, if multiple supply voltages are present), it is
recommended that a clamping diode with low forward voltage
be connected between ST and VS.
POWER SUPPLY DECOUPLING
For most applications, a single 0.1 µF capacitor, CDC, placed
close to the ADXL377 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 because this noise can cause errors
in acceleration measurement.
SELECTING FILTER CHARACTERISTICS:
NOISE/BANDWIDTH TRADE-OFF
The selected accelerometer bandwidth ultimately determines
the measurement resolution (smallest detectable acceleration).
Filtering can be used to lower the noise floor, thereby improving
the resolution of the accelerometer. Resolution is dependent on
If additional decoupling is needed, a 100 Ω (or smaller) resistor
or ferrite bead can be inserted in the supply line. In addition, a
larger bulk bypass capacitor (1 µF or greater) can be added in
parallel to CDC. Ensure that the connection from the ADXL377
ground to the power supply ground is low impedance because
noise transmitted through ground has a similar effect as noise
transmitted through VS.
the analog filter bandwidth at XOUT, YOUT, and ZOUT
.
The output of the ADXL377 has a typical bandwidth of 1000 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 decreased further to reduce noise and
improve resolution.
SETTING THE BANDWIDTH USING CX, CY, AND CZ
The ADXL377 has provisions for band-limiting the XOUT, YOUT
,
and ZOUT pins. A capacitor must be added at each of these pins to
implement low-pass filtering for antialiasing and noise reduction.
The equation for the −3 dB bandwidth is
The ADXL377 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). Limit the bandwidth to the
lowest frequency required by the application to maximize the
resolution and dynamic range of the accelerometer.
f
−3 dB = 1/(2π × 32 kΩ × Cx)
or more simply,
−3 dB = 5 µF/Cx
f
The tolerance of the internal resistor (RFILT) typically varies by as
much as 15% of its nominal value (32 kΩ), and the bandwidth
varies accordingly. A minimum capacitance of 1000 pF for CX,
CY, and CZ is recommended in all cases.
With the single-pole roll-off characteristic, the typical noise of
the ADXL377 is determined by
rms Noise = Noise Density ×
( BW ×1.6)
It is often useful to know the peak value of the noise. Peak-to-
peak noise can only be estimated by statistical methods. Table 5
can be used to estimate the probability of exceeding various peak
values, given the rms value.
Table 4. Filter Capacitor Selection for CX, CY, and CZ
Bandwidth (Hz)
Capacitor (µF)
50
0.10
100
200
500
1000
0.05
0.025
0.01
0.005
Table 5. Estimation of Peak-to-Peak Noise
Percentage of Time That Noise Exceeds
Nominal Peak-to-Peak Value (%)
Peak-to-Peak Value
2 × rms
32
4 × rms
6 × rms
8 × rms
4.6
0.27
0.006
SELF-TEST
The ST pin controls the self-test feature. When this pin is set to
VS, an electrostatic force is exerted on the accelerometer beam.
The resulting movement of the beam allows the user to test
whether the accelerometer is functional. The typical change in
output is −1.08 g (corresponding to −6.5 mV) for the x-axis,
+1.08 g (or +6.5 mV) for the y-axis, and +1.83 g (or +11.5 mV)
for the z-axis. The ST pin can be left open circuit or connected
to ground (GND) in normal use.
Rev. 0 | Page 9 of 12
ADXL377
Data Sheet
AXES OF ACCELERATION SENSITIVITY
Figure 14 shows the axes of sensitivity for the accelerometer. Figure 15 shows the output response when the accelerometer is oriented
parallel to each of these axes.
A
Z
A
Y
A
X
Figure 14. Axes of Acceleration Sensitivity (Corresponding Output Voltage Increases When Accelerated Along the Sensitive Axis)
X
Y
Z
= –1g
= 0g
= 0g
OUT
OUT
OUT
TOP
GRAVITY
X
Y
Z
= 0g
= –1g
= 0g
X
Y
Z
= 0g
= 1g
= 0g
OUT
OUT
OUT
OUT
TOP
TOP
OUT
OUT
TOP
X
Y
Z
= 1g
= 0g
= 0g
OUT
OUT
OUT
X
Y
Z
= 0g
= 0g
= 1g
X
Y
Z
= 0g
= 0g
= –1g
OUT
OUT
OUT
OUT
OUT
OUT
Figure 15. Output Response vs. Orientation to Gravity
Rev. 0 | Page 10 of 12
Data Sheet
ADXL377
LAYOUT AND DESIGN RECOMMENDATIONS
Figure 16 shows the recommended soldering profile; Table 6 describes the profile features. Figure 17 shows the recommended PCB layout
or solder land drawing.
CRITICAL ZONE
tP
T
TO T
L
P
T
P
RAMP-UP
T
L
tL
T
SMAX
T
SMIN
tS
RAMP-DOWN
PREHEAT
t25°C
TIME
Figure 16. Recommended Soldering Profile
Table 6. Recommended Soldering Profile
Profile Feature
Sn63/Pb37
Pb-Free
Average Ramp Rate (TL to TP)
Preheat
3°C/sec max
3°C/sec max
Minimum Temperature (TSMIN
)
100°C
150°C
Maximum Temperature (TSMAX
Time, TSMIN to TSMAX (tS)
Ramp-Up Rate (TSMAX to TL)
Time Maintained Above Liquidous (tL)
Liquidous Temperature (TL)
)
150°C
200°C
60 sec to 120 sec
3°C/sec max
60 sec to 150 sec
183°C
60 sec to 180 sec
3°C/sec max
60 sec to 150 sec
217°C
Peak Temperature (TP)
Time Within 5°C of Actual Peak Temperature (tP)
Ramp-Down Rate (TP to TL)
240°C + 0°C/−5°C
10 sec to 30 sec
6°C/sec max
6 minutes max
260°C + 0°C/−5°C
20 sec to 40 sec
6°C/sec max
8 minutes max
Time 25°C to Peak Temperature (t25°C
)
0.40
MAX
3
0.25
0.50
0.30
MAX
0.50
3
1.60
0.25
CENTER PAD IS NOT
INTERNALLY CONNECTED
BUT SHOULD BE SOLDERED
FOR MECHANICAL INTEGRITY
1.60
DIMENSIONS SHOWN IN MILLIMETERS
Figure 17. Recommended PCB Layout
Rev. 0 | Page 11 of 12
ADXL377
Data Sheet
OUTLINE DIMENSIONS
3.10
3.00 SQ
2.90
0.30
0.25
0.18
PIN 1
INDICATOR
PIN 1
INDICATOR
13
16
0.50
BSC
1
4
12
EXPOSED
PAD
1.70
1.60 SQ
1.50
9
8
5
0.45
0.40
0.35
0.20 MIN
BOTTOM VIEW
TOP VIEW
1.50
1.45
1.40
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
0.05 MAX
0.02 NOM
SECTION OF THIS DATA SHEET.
COPLANARITY
0.08
0.152 REF
SEATING
PLANE
Figure 18. 16-Lead Lead Frame Chip Scale Package [LFCSP_LQ]
3 mm × 3 mm Body, Thick Quad
(CP-16-28)
Dimensions shown in millimeters
ORDERING GUIDE
Measurement Specified
Model1
Range
200 g
200 g
Voltage
Temperature Range
−40°C to +85°C
−40°C to +85°C
Package Description
16-Lead LFCSP_LQ
16-Lead LFCSP_LQ
Evaluation Board
Package Option
Branding
Y4P
Y4P
ADXL377BCPZ-RL
ADXL377BCPZ-RL7
EVAL-ADXL377Z
3 V
3 V
CP-16-28
CP-16-28
1 Z = RoHS Compliant Part.
©2012 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D10765-0-9/12(0)
Rev. 0 | Page 12 of 12
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