ADXL337 View Datasheet(PDF) - Analog Devices
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ADXL337 Datasheet PDF : 16 Pages
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ADXL337
USE WITH OPERATING VOLTAGES OTHER THAN 3 V
The ADXL337 is tested and specified at VS = 3 V; however, it
can be powered with VS as low as 1.8 V or as high as 3.6 V. Note
that some performance parameters change as the supply voltage
is varied.
The ADXL337 output is ratiometric; therefore, the output
sensitivity (or scale factor) varies proportionally to the supply
voltage. At VS = 3.6 V, the output sensitivity is typically 360 mV/g.
At VS = 2 V, the output sensitivity is typically 195 mV/g.
The zero g bias output is also ratiometric; therefore, the zero g
output is nominally equal to VS/2 at all supply voltages.
The output noise is not ratiometric but is absolute in volts;
therefore, the noise density decreases as the supply voltage
increases. This is because the scale factor (mV/g) increases
while the noise voltage remains constant. At VS = 3.6 V, the X-
and Y-axis noise density is typically 120 μg/√Hz, and at VS =
2 V, the X- and Y-axis noise density is typically 270 μg/√Hz.
Self test response in g is roughly proportional to the square of
the supply voltage. However, when ratiometricity of sensitivity
is factored in with supply voltage, the self test response in volts
is roughly proportional to the cube of the supply voltage. For
example, at VS = 3.6 V, the self test response for the ADXL337 is
approximately −560 mV for the X-axis, +560 mV for the Y-axis,
and +950 mV for the Z-axis.
At VS = 2 V, the self test response is approximately −96 mV for
the X-axis, +96 mV for the Y-axis, and −163 mV for the Z-axis.
The supply current decreases as the supply voltage decreases.
Typical current consumption at VS = 3.6 V is 375 μA, and
typical current consumption at VS = 2 V is 200 μA.
AXES OF ACCELERATION SENSITIVITY
The axes of sensitivity for the accelerometer are shown in Figure 23,
and Figure 24 shows the output response when the accelerometer is
oriented parallel to each of these axes.
AZ
AY
TOP
AX
Figure 23. Axes of Acceleration Sensitivity, Corresponding Output Voltage
Increases When Accelerated Along the Sensitive Axis
XOUT = –1g
YOUT = 0g
ZOUT = 0g
TOP
XOUT = 0g
YOUT = 1g
ZOUT = 0g
TOP
TOP
XOUT = 0g
YOUT = –1g
ZOUT = 0g
GRAVITY
TOP
XOUT = 1g
YOUT = 0g
ZOUT = 0g
TOP
XOUT = 0g
YOUT = 0g
ZOUT = 1g
Figure 24. Output Response vs. Orientation to Gravity
XOUT = 0g
YOUT = 0g
ZOUT = –1g
Rev. 0 | Page 12 of 16
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