ADXL202 Datasheet, PDF (1/11 Pages) Analog Devices – Low Cost +-2 g/+-10 g Dual Axis iMEMS Accelerometers with Digital Output

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Low Cost ؎2 g/؎10 g Dual Axis
iMEMS^® Accelerometers
with Digital Output
ADXL202/ADXL210
FEATURES
2-Axis Acceleration Sensor on a Single IC Chip
Measures Static Acceleration as Well as Dynamic
Acceleration
Duty Cycle Output with User Adjustable Period
Low Power <0.6 mA
Faster Response than Electrolytic, Mercury or Thermal
Tilt Sensors
Bandwidth Adjustment with a Single Capacitor Per Axis
5 mg Resolution at 60 Hz Bandwidth
+3 V to +5.25 V Single Supply Operation
1000 g Shock Survival
APPLICATIONS
2-Axis Tilt Sensing
Computer Peripherals
Inertial Navigation
Seismic Monitoring
Vehicle Security Systems
Battery Powered Motion Sensing
GENERAL DESCRIPTION
The ADXL202/ADXL210 are low cost, low power, complete
2-axis accelerometers with a measurement range of either
± 2 g/± 10 g. The ADXL202/ADXL210 can measure both dy-
namic acceleration (e.g., vibration) and static acceleration (e.g.,
gravity).
The outputs are digital signals whose duty cycles (ratio of pulse-
width to period) are proportional to the acceleration in each of
the 2 sensitive axes. These outputs may be measured directly
with a microprocessor counter, requiring no A/D converter or
glue logic. The output period is adjustable from 0.5 ms to 10 ms
via a single resistor (R_SET). If a voltage output is desired, a
voltage output proportional to acceleration is available from the
X_FILT and Y_FILT pins, or may be reconstructed by filtering the
duty cycle outputs.
The bandwidth of the ADXL202/ADXL210 may be set from
0.01 Hz to 5 kHz via capacitors C_X and C_Y. The typical noise
floor is 500 µg/√Hz allowing signals below 5 mg to be resolved
for bandwidths below 60 Hz.
The ADXL202/ADXL210 is available in a hermetic 14-lead
Surface Mount CERPAK, specified over the 0°C to +70°C
commercial or –40°C to +85°C industrial temperature range.
FUNCTIONAL BLOCK DIAGRAM
+3.0V TO +5.25V
V_DD
V_DD
C_X
X_FILT
SELF TEST
ADXL202/
X SENSOR
R_FILT
ADXL210
32k⍀
X OUT
C_DC
DEMOD
OSCILLATOR
DUTY
CYCLE
MODULATOR
(DCM)
C
O
U
N ^␮P
T
DEMOD
R_FILT
32k⍀
E
Y OUT
R
Y SENSOR
COM
Y_FILT
T2
C_Y
R_SET
T2
iMEMS is a registered trademark of Analog Devices, Inc.
REV. B
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.
T1
A(g) = (T1/T2 – 0.5)/12.5%
0g = 50% DUTY CYCLE
T2 = R_SET/125M⍀
A_IN2 =
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone]
© Analog Devices, Inc., 1999