Low Cost
±1.5
g
Tri Axis Accelerometer with
Ratiometric Outputs
MXR9500G/M
FEATURES
Low cost
RoHS compliant
Resolution better than 1 milli-g
Tri-axis accelerometer in a single package.
On chip mixed signal processing
No moving parts
No loose particle issues
>50,000
g
shock survival rating
SMT package: 7mm
X
7mm
X
1.8mm
2.7V to 3.6V single supply continuous operation
No adjusting external components needed
X
Sensor
Gain Adjust
Temp
Comp
A/D
D/A
LPF
Xout
Y
Sensor
Gain Adjust
Temp
Comp
A/D
D/A
LPF
Yout
Z
Sensor
Gain Adjust
Temp
Comp
A/D
D/A
LPF
Zout
VSA1
Reference
Digital Interface
Clock
VSA2
APPLICATIONS
GPS
–
Electronic Compass Tilt Correction/Navigation
Consumer –
LCD projectors, pedometers, blood pressure
Monitor, digital cameras/MP3 players
I
nformation Appliances
– Computer
Peripherals/PDA’s/Mouse Smart Pens/Cell Phones
Gaming
– Joystick/RF Interface/Menu Selection/Tilt
Sensing
Security
– Gas Line/Elevator/Fatigue Sensing
GENERAL DESCRIPTION
The MXR9500G/M is a low cost, tri axis accelerometer
fabricated on a standard, submicron CMOS process. It is a
complete sensing system with on-chip mixed signal
processing. The MXR9500G/M measures acceleration with
a full-scale range of
±1.5
g
and a sensitivity of 500mV/g
@3.0V at 25
°C
. It can measure both dynamic acceleration
(e.g. vibration) and static acceleration (e.g. gravity). The
MXR9500G/M design is based on heat convection and
requires no solid proof mass. This eliminates stiction and
particle problems associated with competitive devices and
provides shock survival greater than 50,000
g,
leading to
significantly lower failure rate and lower loss due to
handling during PCB assembly and at customer field
application.
VDD1
VDD2
VDD3
DI1
SCK1
DI2
SCK2
FUNCTIONAL BLOCK DIAGRAM
The MXR9500G/M provides three ratiometric analog
outputs that are set to 50% of the power supply voltage at
zero g.
The Max. noise floor is 1 mg/
Hz
allowing signals
below 1 milli-g to be resolved at 1 Hz bandwidth.
The
MXR9500G/M is packaged in a hermetically sealed,
surface mount LCC 16pins package (7 mm x 7 mm x 1.8
mm height) and is operational over a
-40°C to +85°C (M) and
0°C to +70°C (G) temperature range.
I
2
C fast mode interface is soon available in the next generation
chip.
Information furnished by MEMSIC is believed to be accurate and reliable. However,
no responsibility is assumed by MEMSIC for its use, nor for any infringements of
patents or other rights of third parties which may result from its use. No license is
granted by implication or otherwise under any patent or patent rights of MEMSIC.
©MEMSIC,
Inc.
800 Turnpike St., Suite 202, North Andover, MA 01845
Tel: 978.738.0900
Fax: 978.738.0196
www.memsic.com
MEMSIC MXR9500G/M Preliminary
Page 1 of 5
8/26/2005
MXR9500G/M SPECIFICATIONS
(Measurements @ 25°C, Acceleration = 0
g
unless otherwise noted; VDD1,VDD3 = 3.0V unless
otherwise specified)
Parameter
Measurement Range
1
Nonlinearity
Alignment Error
2
Transverse Sensitivity
3
Sensitivity
Sensitivity Change Over Temperature
Zero
g
Offset Bias Level
Zero
g
Offset TC
Conditions
Each Axis
Best fit straight line
X, Y-axis
Z-axis
Min
±1.5
Typ
0.5
±
1.0
±
3.0
±
2.0
500
15
1.50
0.0
Max
1.0
Units
g
% of FS
degrees
degrees
%
mV/g
%
V
g
475
∆
from 25°C
1.45
-0.1
∆
from 25°C, based on
500mV/g
X,Y-axis
Z-axis
Output High
Output Low
X,Y-axis
Z-axis
@1Hz BW
@-3dB
@2.7V-3.6V
2.7
525
1.55
+0.1
1.0
1.5
2.8
0.2
0.6
0.9
0.5
17
75
3.0
4.2
1
100
3.6
0.1
+70
+85
Normal Output Range
Noise Density, RMS
Resolution
Frequency Response
Output Drive Capability
Turn-On Time
4
Operating Voltage Range
Supply Current
Power Down Current
Operating Temperature Range
mg/°C
mg/°C
V
V
mg/
Hz
mg/
Hz
mg
Hz
µA
mS
V
mA
uA
°C
°C
MXR9500G
MXR9500M
0
-40
NOTES
1
2
Guaranteed by measurement of initial offset and sensitivity.
Alignment error is specified as the angle between the true and indicated axis of
sensitivity.
3
Cross axis sensitivity is the algebraic sum of the alignment and the inherent
sensitivity errors.
4
Output settled to within
±17mg.
MEMSIC MXR9500G/M
Preliminary
Page 2 of 5
8/26/2005
ABSOLUTE MAXIMUM RATINGS*
………………...-0.5 to +7.0V
Supply Voltage (V
DD
)
Storage Temperature ……….…………-65°C to +150°C
Acceleration ……………………………………..50,000
g
*Stresses above those listed under Absolute Maximum Ratings may cause permanent
damage to the device. This is a stress rating only; the functional operation of the
device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.
6
5
4
3
2
7
8
+X
1
+Y
9
10
11
+Z
16
15
Pin Description: LCC-16 Package
Pin
Name
Description
1
NC
Do Not Connect
2
Zout
Z Channel Output
3
VSA2
Connect to Ground
4
VDD1
2.7V to 3.6V
5
DI1
Power Down Pin
6
SCK1
Connect to Ground
7
NC
Do Not Connect
8
VSA1
Connect to Ground
9
NC
Do Not Connect
10
NC
Do Not Connect
11
VDD2
2.7V to 3.6V
12
Yout
Y Channel Output
13
Xout
X Channel Output
14
VDD3
2.7V to 3.6V
15
SCK2
Connect to Ground
16
DI2
Power Down Pin
Ordering Guide
Model
MXR9500GZ
MXR9500MZ
12
13
14
(Top View)
+X
+Z
(Side View)
Temperature
Range
0 to 70°C
-40 to 85°C
Package
LCC16,
RoHS compliant
LCC16,
RoHS compliant
All parts are shipped in tape and reel packaging.
Caution:
ESD (electrostatic discharge) sensitive device.
MEMSIC MXR9500G/M
Preliminary
Page 3 of 5
8/26/2005
THEORY OF OPERATION
The MEMSIC device is a complete tri-axis acceleration
measurement system in a single package fabricated on
CMOS IC process. The device operation is based on heat
transfer by natural convection and operates like other
accelerometers having a proof mass except it is a gas in
MEMSIC sensor.
Heat source, centered in the silicon chip is suspended
across a cavity. Equally spaced aluminum/polysilicon
thermopiles (groups of thermocouples) are located
equidistantly on all four sides of the heat source. Under
zero acceleration, a temperature gradient is symmetrical
about the heat source, so that the temperature is the same at
all four thermopiles, causing them to output the same
voltage.
Acceleration in any direction will disturb the temperature
profile, due to free convection heat transfer, causing it to be
asymmetrical. The temperature, and hence voltage output
of the four thermopiles will then be different. The
differential voltage at the thermopile outputs is directly
proportional to the acceleration. Please visit the MEMSIC
website at www.memsic.com for a picture/graphic
description of the free convection heat transfer principle.
Xout
– This pin is the analog output of the X-axis
acceleration sensor.
Yout
–
This pin is the analog output of the Y-axis
acceleration sensor
Zout
–
This pin is the analog output of the Z-axis
acceleration sensor.
POWER SUPPLY NOISE REJECTION
One capacitor is recommended for best rejection of power
supply noise. The capacitor should be located as close as
possible to the device supply pin (VDD1,VDD3). The
capacitor lead length should be as short as possible, and
surface mount capacitor is preferred. For typical
applications, the capacitor can be ceramic 0.1 µF.
Power Supply
VDD1
VDD3
MXR9500G/M PIN DESCRIPTIONS
VDD1, VDD2, VDD3–
These pins are the supply input for
the circuits and the sensor heater in the
accelerometer
. The
DC voltage should be 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.
VSA1, VSA2–
These pins are ground pin for the
accelerometer.
SCK1, SCK2–
These pins are for factory used only, should
be connect to ground.
DI1, DI2–
These pins are the power down control pin. Pull
these pins HIGH will 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.
In normal operation mode, this pin should be
connected to Ground.
MEMSIC
Accelerometer
PCB LAYOUT AND FABRICATION SUGGESTIONS
1.
2.
It is best to solder a 0.1uF capacitor directly across
VDD1, VSA1 and VDD3, VSA2 pin.
Robust low inductance ground wiring should be used.
MEMSIC MXR9500G/M
Preliminary
Page 4 of 5
8/26/2005
PACKAGE DRAWING
0.5x45
MEMSIC MXR9500G/M
Preliminary
Page 5 of 5
8/26/2005
嵌入式系统
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