ADXL202E Datasheet, PDF (1/12 Pages) Analog Devices – Low-Cost +-2 g Dual-Axis Accelerometer with Duty Cycle Output

a Low-Cost ؎2 g Dual-Axis Accelerometer
with Duty Cycle Output
ADXL202E*
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
FUNCTIONAL BLOCK DIAGRAM
3V TO 5.25V
V_DD
C_X
X_FILT
SELF-TEST
X SENSOR
DEMOD
R_FILT
32k⍀
ANALOG
X_{OUT C}
O
C_DC
OSCILLATOR
ADXL202E
TO
DUTY
U
N ␮P
CYCLE
T
DEMOD
Y SENSOR
R_FILT
32k⍀
(ADC)
E
Y_OUT ^R
COM
Y_FILT
T2
C_Y
R_SET
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 Ϯ2 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 Ï« 5 mm Ï« 2 mm 8-lead
hermetic LCC package.
*Patents Pending
REV. A
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© Analog Devices, Inc., 2000