REV.A
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which may result from its use. No license is granted by implication or
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a
ADXL202E*
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
Low-Cost H115502 g Dual-Axis Accelerometer
with Duty Cycle Output
FUNCTIONAL BLOCK DIAGRAM
ANALOG
TO
DUTY
CYCLE
(ADC)
C
O
U
N
T
E
R
H9262P
X
OUT
Y
OUT
DEMOD
DEMOD
R
FILT
32kH9024
R
FILT
32kH9024
ADXL202E
R
SET
T2
C
Y
Y
FILT
SELF-TEST
X
FILT
C
X
OSCILLATOR
COM
Y SENSOR
X SENSOR
3V TO 5.25V
V
DD
C
DC
T1
T2
A(g) = (T1/T2 – 0.5)/12.5%
0g = 50% DUTY CYCLE
T2 = R
SET
/125MH9024
FEATURES
2-Axis Acceleration Sensor on a Single IC Chip
5mm H11547 5mm H11547 2mm Ultrasmall Chip Scale Package
2mg Resolution at 60Hz
Low-Power < 0.6mA
Direct Interface to Low-Cost Microcontrollers via
Duty Cycle Output
BW Adjustment with a Single Capacitor
3V to 5.25V Single Supply Operation
1000g 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
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 H110062 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
).
*Patents Pending
The typical noise floor is 200 H9262g√Hz, allowing signals below
2mg (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 H11003 5 mm H11003 2 mm 8-lead
hermetic LCC package.