EVAL-ADXL327Z Analog Devices Inc, EVAL-ADXL327Z Datasheet - Page 10
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EVAL-ADXL327Z
Manufacturer Part Number
EVAL-ADXL327Z
Description
Accelerometer Eval. Board
Manufacturer
Analog Devices Inc
Series
iMEMS®r
Specifications of EVAL-ADXL327Z
Silicon Manufacturer
Analog Devices
Application Sub Type
Accelerometer - Three-Axis
Kit Application Type
Sensing - Motion / Vibration / Shock
Silicon Core Number
ADXL327
Sensor Type
Accelerometer, 3 Axis
Sensing Range
±2.5g
Interface
Analog
Sensitivity
420mV/g
Voltage - Supply
1.8 V ~ 3.6 V
Embedded
*
Utilized Ic / Part
ADXL327
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
ADXL327
THEORY OF OPERATION
The ADXL327 is a complete 3-axis acceleration measurement
system. The ADXL327 has a measurement range of ±2 g minimum.
It contains a polysilicon surface micromachined sensor and signal
conditioning circuitry to implement an open-loop acceleration
measurement architecture. The output signals are analog voltages
that are proportional to acceleration. The accelerometer can
measure the static acceleration of gravity in tilt sensing applications,
as well as dynamic acceleration, resulting from motion, shock,
or vibration.
The sensor is a polysilicon surface micromachined structure
built on top of a silicon wafer. Polysilicon springs suspend the
structure over the surface of the wafer and provide a resistance
against acceleration forces. Deflection of the structure is measured
using a differential capacitor that consists of independent fixed
plates and plates attached to the moving mass. The fixed plates
are driven by 180° out-of-phase square waves. Acceleration deflects
the moving mass and unbalances the differential capacitor resulting
in a sensor output whose amplitude is proportional to acceleration.
Phase-sensitive demodulation techniques are then used to
determine the magnitude and direction of the acceleration.
The demodulator output is amplified and brought off-chip through
a 32 kΩ resistor. The user then sets the signal bandwidth of the
device by adding a capacitor. This filtering improves measurement
resolution and helps prevent aliasing.
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MECHANICAL SENSOR
The ADXL327 uses a single structure for sensing the X, Y, and Z axes.
As a result, the three axes sense directions are highly orthogonal
with little cross-axis sensitivity. Mechanical misalignment of the
sensor die to the package is the chief source of cross-axis sensitivity.
Mechanical misalignment can, of course, be calibrated out at
the system level.
PERFORMANCE
Rather than using additional temperature compensation circuitry,
innovative design techniques ensure that high performance is
built-in to the ADXL327. As a result, there is neither quantization
error nor nonmonotonic behavior, and temperature hysteresis is
very low (typically <3 mg over the −25°C to +70°C temperature
range).