Low-Cost 2 g Dual-Axis Accelerometer
with Duty Cycle Output
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
GENERAL DESCRIPTION
The ADXL202E is a low-cost, low-power, complete 2-axis accelerometer
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., vibration)
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 microprocessor
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 (RSET).
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 CX and
CY at the XFILT and YFILT pins. An analog output can be reconstructed
by filtering the duty cycle output.
The ADXL202E is available in 5 mm 5 mm 2 mm 8-lead
hermetic LCC package.
