a
Low-Cost 2
g
Dual-Axis Accelerometer
with Duty Cycle Output
ADXL202E*
FUNCTIONAL BLOCK DIAGRAM
3V TO 5.25V
C
X
V
DD
X SENSOR
DEMOD
C
DC
OSCILLATOR
R
FILT
32k
ANALOG
TO
DUTY
CYCLE
(ADC)
Y
OUT
Y
FILT
C
Y
T2
R
SET
X
FILT
SELF-TEST
FEATURES
2-Axis Acceleration Sensor on a Single IC Chip
5 mm 5 mm 2 mm Ultrasmall Chip Scale Package
2 mg Resolution at 60 Hz
Low-Power < 0.6 mA
Direct Interface to Low-Cost Microcontrollers via
Duty Cycle Output
BW Adjustment with a Single Capacitor
3 V to 5.25 V Single Supply Operation
1000
g
Shock Survival
APPLICATIONS
2-Axis Tilt Sensing with Faster Response than
Electrolytic, Mercury, or Thermal Sensors
Computer Peripherals
Information Appliances
Alarms and Motion Detectors
Disk Drives
Vehicle Security
X
OUT
ADXL202E
R
FILT
32k
DEMOD
Y SENSOR
COM
C
O
U
N
T
E
R
P
T2
T1
A(g) = (T1/T2 – 0.5)/12.5%
0g = 50% DUTY CYCLE
T2 = R
SET
/125M
GENERAL DESCRIPTION
The ADXL202E is a low-cost, low-power, complete 2-axis acceler-
ometer with a digital output, all on a single monolithic IC. It is an
improved version of the ADXL202AQC/JQC. The ADXL202E
will measure accelerations with a full-scale range of 2
g.
The
ADXL202E can measure both dynamic acceleration (e.g., vibra-
tion) and static acceleration (e.g., gravity).
The outputs are analog voltage or digital signals whose duty cycles
(ratio of pulsewidth to period) are proportional to acceleration.
The duty cycle outputs can be directly measured by a micro-
processor counter, without an A/D converter or glue logic. The
duty cycle period is adjustable from 0.5 ms to 10 ms via a single
resistor (R
SET
).
The typical noise floor is 200
g√Hz,
allowing signals below
2 mg (at 60 Hz bandwidth) to be resolved.
The bandwidth of the accelerometer is set with capacitors C
X
and
C
Y
at the X
FILT
and Y
FILT
pins. An analog output can be recon-
structed by filtering the duty cycle output.
The ADXL202E is available in 5 mm
hermetic LCC package.
5 mm
2 mm 8-lead
*Patents
Pending
REV. A
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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
World Wide Web Site: http://www.analog.com
Fax: 781/326-8703
© Analog Devices, Inc., 2000
ADXL202E–SPECIFICATIONS
Parameter
SENSOR INPUT
Measurement Range
2
Nonlinearity
Alignment Error
3
Alignment Error
Cross-Axis Sensitivity
4
SENSITIVITY
Duty Cycle per
g
Duty Cycle per
g
Sensitivity X
FILT
, Y
FILT
Sensitivity X
FILT
, Y
FILT
Temperature Drift
5
ZERO
g
BIAS LEVEL
0
g
Duty Cycle
0
g
Duty Cycle
0
g
Voltage X
FILT
, Y
FILT
0
g
Voltage X
FILT
, Y
FILT
0
g
Duty Cycle vs. Supply
0
g
Offset vs. Temperature
5
NOISE PERFORMANCE
Noise Density
FREQUENCY RESPONSE
3 dB Bandwidth
Sensor Resonant Frequency
FILTER
R
FILT
Tolerance
Minimum Capacitance
SELF-TEST
Duty Cycle Change
DUTY CYCLE OUTPUT STAGE
F
SET
Output High Voltage
Output Low Voltage
T2 Drift vs. Temperature
Rise/Fall Time
POWER SUPPLY
Operating Voltage Range
Quiescent Supply Current
Turn-On Time
TEMPERATURE RANGE
Specified Performance AE
Operating Range
Conditions
Each Axis
Best Fit Straight Line
(T
A
= T
MIN
to T
MAX
, T
A
= 25 C for J Grade only, V
DD
= 5 V, R
SET
= 125 k ,
Acceleration = 0
g,
unless otherwise noted.)
TPC
1
Graph
Min
±
2
X
0.2
±
1
0.01
±
2
10.5
9.0
265
140
12.5
11
312
167
±
0.5
50
50
2.5
1.5
1.0
2.0
200
6
10
±
15
1000
10
0.7
V
S
– 200 mV
50
200
3
5.25
1.0
3.0
160
–40
–40
0.6
C
FILT
+ 0.3
1.3
200
50
200
5.25
1.0
0.7
V
S
– 200 mV
1000
10
1.3
200
14.5
13.0
360
195
10
8.5
250
140
ADXL202JE
Typ
Max
Min
±
2
0.2
±
1
0.01
±
2
12.5
11
312
167
±
0.5
50
50
2.5
1.5
1.0
2.0
200
6
10
±
15
15
13.5
375
200
ADXL202AE
Typ
Max
Unit
g
% of FS
Degrees
Degrees
%
%/g
%/g
mV/g
mV/g
%
%
%
V
V
%/V
mg/ C
µg√Hz
rms
kHz
kHz
%
pF
%
kHz
V
mV
ppm/ C
ns
V
mA
ms
C
C
X Sensor to Y Sensor
X
Each Axis
T1/T2, V
DD
= 5 V
T1/T2, V
DD
= 3 V
V
DD
= 5 V
V
DD
= 3 V
Delta from 25 C
Each Axis
T1/T2, V
DD
= 5 V
T1/T2, V
DD
= 3 V
V
DD
= 5 V
V
DD
= 3 V
Delta from 25 C
@ 25 C
At Pins X
FILT
, Y
FILT
X
X
X
X
X
X
X
X
X
X
X
X
34
31
2.1
1.2
66
69
2.9
1.8
4.0
30
31
2.0
1.2
70
69
3.0
1.8
4.0
1000
32 kΩ Nominal
At Pins X
FILT
, Y
FILT
Self-Test “0” to “1”
R
SET
= 125 kΩ
I = 25
µA
I = 25
µA
C
FILT
in
µF
160
0.6
C
FILT
+ 0.3
0
70
+85
+85
NOTES
1
Typical Performance Characteristics.
2
Guaranteed by measurement of initial offset and sensitivity.
3
Alignment error is specified as the angle between the true and indicated axis of sensitivity (see TPC 15).
4
Cross-axis sensitivity is the algebraic sum of the alignment and the inherent sensitivity errors.
5
Defined as the output change from ambient to maximum temperature or ambient to minimum temperature.
Specifications subject to change without notice.
–2–
REV. A
ADXL202E
ABSOLUTE MAXIMUM RATINGS*
PIN CONFIGURATION
V
DD
8
Acceleration (Any Axis, Unpowered for 0.5 ms) . . . . . . 1000
g
Acceleration (Any Axis, Powered for 0.5 ms) . . . . . . . . . . 500
g
+V
S
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +6.0 V
Output Short Circuit Duration, (Any Pin to Common)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Indefinite
Operating Temperature . . . . . . . . . . . . . . . . –55 C to +125 C
Storage Temperature . . . . . . . . . . . . . . . . . . –65 C to +150 C
*Stresses
above those listed under Absolute Maximum Ratings may cause per ma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those indicate in the opera tional
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
X
FILT
Y
FILT
X
OUT
7
6
5
4
1
2
3
ST
T2
COM
Y
OUT
BOTTOM VIEW
PIN FUNCTION DESCRIPTIONS
Drops onto hard surfaces can cause shocks of greater than 1000
g
and exceed the absolute maximum rating of the device. Care
should be exercised in handling to avoid damage.
Package Characteristics
Pin
No.
1
2
3
4
5
6
7
8
Mnemonic
ST
T2
COM
Y
OUT
X
OUT
Y
FILT
X
FILT
V
DD
Description
Self-Test
Connect R
SET
to Set T2 Period
Common
Y-Channel Duty Cycle Output
X-Channel Duty Cycle Output
Y-Channel Filter Pin
X-Channel Filter Pin
3 V to 5.25 V
Package
Weight
8-Lead LCC
JA
JC
Device
<1.0 grams
120°C/W
tbd°C/W
ORDERING GUIDE
Model
ADXL202JE
ADXL202AE
No.
of Axes
2
2
Specified
Voltage
3 V to 5 V
3 V to 5 V
Temperature
Range
0 to 70 C
–40 C to +85 C
Package
Description
8-Lead LCC
8-Lead LCC
Package
Option
E-8
E-8
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
the ADXL202E 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.
WARNING!
ESD SENSITIVE DEVICE
REV. A
–3–
ADXL202E –Typical Performance Characteristics*
V
DD
= 3 V
16
14
12
PERCENT OF PARTS
PERCENT OF PARTS
V
DD
= 5 V
18
16
14
12
10
8
6
4
2
0
2.05
2.14
2.23
2.31
2.40 2.48
VOLTS
2.57
2.65
2.74
2.82
10
8
6
4
2
0
1.28
1.32
1.36
1.41
1.45 1.49
VOLTS
1.53
1.58
1.62
1.66
TPC 1. X-Axis Zero g Bias Distribution at X
FILT
, V
DD
= 3 V
TPC 4. X-Axis Zero g Bias Distribution at X
FILT
, V
DD
= 5 V
16
14
25
20
12
PERCENT OF PARTS
PERCENT OF PARTS
10
8
6
4
15
10
5
2
0
1.25
1.31
1.36
1.42
1.48
VOLTS
1.53
1.59
1.65
0
2.05
2.14
2.23
2.31
2.40 2.48
VOLTS
2.57
2.65
2.74
2.82
TPC 2. Y-Axis Zero g Bias Distribution at Y
FILT
, V
DD
= 3 V
TPC 5. Y-Axis Zero g Bias Distribution at Y
FILT
, V
DD
= 5 V
25
25
20
PERCENT OF PARTS
20
PERCENT OF PARTS
15
15
10
10
5
5
0
0.142
0
0.148
0.155
0.162
0.169
V/g
0.176
0.182
0.189
0.26
0.28
0.29
0.30
V/g
0.32
0.33
0.34
TPC 3. X-Axis Sensitivity Distribution at X
FILT
, V
DD
= 3 V
TPC 6. X-Axis Sensitivity Distribution at X
FILT
, V
DD
= 5 V
*Data
taken from 4500 parts over 3 lots minimum.
–4–
REV. A
ADXL202E
V
DD
= 3 V
25
25
V
DD
= 5 V
20
PERCENT OF PARTS
20
PERCENT OF PARTS
15
15
10
10
5
5
0
0.142
0
0.148
0.155
0.162
0.169
V/g
0.176
0.182
0.189
0.26
0.27
0.29
0.30
0.31
V/g
0.33
0.34
0.35
TPC 7. Y-Axis Sensitivity Distribution at Y
FILT
, V
DD
= 3 V
TPC 10. Y-Axis Sensitivity Distribution at Y
FILT
, V
DD
= 5 V
30
25
25
20
PERCENT OF PARTS
20
PERCENT OF PARTS
15
15
10
10
5
5
0
9.50
9.90
10.4
10.8
11.3
11.8
PERCENT DUTY CYCLE/g
12.2
12.7
0
10.3
10.8
11.3
11.8
12.3
12.8
PERCENT DUTY CYCLE/g
13.3
13.8
TPC 8. X-Axis Sensitivity at X
OUT
, V
DD
= 3 V
TPC 11. X-Axis Sensitivity at X
OUT
, V
DD
= 5 V
20
18
16
PERCENT OF PARTS
PERCENT OF PARTS
25
20
14
12
10
8
6
4
2
0
9.50
9.90
10.4
10.8
11.3
11.8
PERCENT DUTY CYCLE/g
12.2
12.7
15
10
5
0
10.6
11.0
11.6
12.0
12.6
13.0
PERCENT DUTY CYCLE/g
13.6
14.0
TPC 9. Y-Axis Sensitivity at Y
OUT
, V
DD
= 3 V
TPC 12. Y-Axis Sensitivity at Y
OUT
, V
DD
= 5 V
REV. A
–5–
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