MXR6999MP MEMSIC, MXR6999MP Datasheet - Page 4

• Manufacturer Part Number: MXR6999MP
• Description: ACCELEROMETER, 2 AXIS, ±1G, LCC8
• Manufacturer: MEMSIC

Specifications of MXR6999MP

• No. Of Axes: 2
• Sensor Case Style: LCC
• No. Of Pins: 8
• Supply Voltage Range: 2.7V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Operating Temperature Max: 85°C
• Operating: RoHS Compliant
• Acceleration Range: ±1g
• Sensitivity Per Axis: 1000mV / G
• Rohs Compliant: Yes

PIN DESCRIPTIONS
V
heater in the
between 2.7 and 3.6 volts. Refer to the section on PCB
layout and fabrication suggestions for guidance on external
parts and connections recommended.
COM– This is the ground pin for the
TP– This pin should be connected to ground.
Xout – This pin is the ratiometric output of the X-axis
acceleration sensor. The user should ensure the load
impedance is sufficiently high as to not source/sink >100µA
typical.
programmed at the factory to be the same as the sensitivity
for the y-axis, the
non-equal sensitivities on the x- and y-axes. Contact the
factory for additional information.
Yout –
acceleration sensor. The user should ensure the load
impedance is sufficiently high as to not source/sink >100µA
typical.
programmed at the factory to be the same as the sensitivity
for the x-axis, the
non-equal sensitivities on the x- and y-axes. Contact the
factory for additional information.
PD–
put the accelerometer into power down mode. When the part goes
into power down mode, the total current will be smaller than 0.1uA
at 3V.
Ground.
DISCUSSION
RESOLUTION
Tilt Applications: One of the most popular applications
of the MEMSIC accelerometer product line is in
tilt/inclination measurement. An accelerometer uses the
force of gravity as an input to determine the inclination
angle of an object.
A MEMSIC accelerometer is most sensitive to changes in
position, or tilt, when the accelerometer’s sensitive axis is
perpendicular to the force of gravity, or parallel to the
Earth’s surface. Similarly, when the accelerometer’s axis
is parallel to the force of gravity (perpendicular to the
Earth’s surface), it is least sensitive to changes in tilt.
Following table and figure help illustrate the output changes
in the X- and Y-axes as the unit is tilted from +90° to 0°.
Notice that when one axis has a small change in output per
degree of tilt (in mg), the second axis has a large change in
output per degree of tilt. The complementary nature of
these two signals permits low cost accurate tilt sensing to be
achieved with the MEMSIC device (reference application
note AN-00MX-007).
MEMSIC MXR6999G/M Rev.D
DD
In normal operation mode, this pin should be connected to
– This is the supply input for the circuits and the sensor
Pin 1 is the power down control pin. Pull this pin HIGH will
This pin is the ratiometric output of the Y-axis
While the sensitivity of this axis has been
While the sensitivity of this axis has been
accelerometer
OF
accelerometer
accelerometer
TILT
.
The DC voltage should be
APPLICATIONS
can be programmed for
can be programmed for
accelerometer
.
AND
Page 4 of 6
X-Axis
Orientation
To Earth’s
Surface
(deg.)
Resolution: The accelerometer resolution is limited by
noise. The output noise will vary with the measurement
bandwidth. With the reduction of the bandwidth, by
applying an external low pass filter, the output noise drops.
Reduction of bandwidth will improve the signal to noise
ratio and the resolution. The output noise scales directly
with the square root of the measurement bandwidth. The
maximum amplitude of the noise, its peak- to- peak value,
approximately defines the worst case resolution of the
measurement. With a simple RC low pass filter, the rms
noise is calculated as follows:
Noise (mg rms) = Noise(mg/ Hz ) *
The peak-to-peak noise is approximately equal to 6.6 times
the rms value (for an average uncertainty of 0.1%).
POWER SUPPLY NOISE REJECTION
One capacitor is recommended for best rejection of power
supply noise (reference figure below). The capacitor should
be located as close as possible to the device supply pin
(V
possible, and surface mount capacitor is preferred. For
typical applications, the capacitor can be ceramic 0.1 µF.
DD
90
85
80
70
60
45
30
20
10
5
0
). The capacitor lead length should be as short as
Accelerometer Position Relative to Gravity
X Output
Changes in Tilt for X- and Y-Axes
1.000
0.996
0.985
0.940
0.866
0.707
0.500
0.342
0.174
0.087
0.000
(g)
X-Axis
per deg.
Change
of tilt
(mg)
12.23
15.04
16.35
17.16
17.37
17.45
0.15
1.37
2.88
5.86
8.59
Y Output
(
Bandwidth
0.000
0.087
0.174
0.342
0.500
0.707
0.866
0.940
0.985
0.996
1.000
(g)
Y-Axis
2/26/2007
(
Hz
per deg.
Change
17.45
17.37
17.16
16.35
15.04
12.23
of tilt
(mg)
* )
8.59
5.86
2.88
1.37
0.15
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