Improved, Ultra Low Noise
±1.7
g
Dual Axis Accelerometer with
Absolute Outputs
MXA2500G/M
FEATURES
Resolution better than 1 milli-g
Dual axis accelerometer fabricated on a monolithic CMOS IC
On chip mixed mode signal processing
No moving parts
50,000
g
shock survival rating
17 Hz bandwidth expandable to >160 Hz
3.0V to 5.25V single supply continuous operation
Continuous self test
Independent axis programmability (special order)
Internal Sensitivity Compensated
Sck
(optional)
Internal
Oscillator
Temperature
Sensor
T
OUT
CLK
Voltage
Reference
V
REF
Heater
Control
Continous
Self Test
X axis
Low Pass
Filter
A
OUTX
APPLICATIONS
Automotive –
Vehicle Security/Vehicle Stability control/
Headlight Angle Control/Tilt Sensing
Security
– Gas Line/Elevator/Fatigue Sensing/Computer Security
Information Appliances
– Computer Peripherals/PDA’s/Mouse
Smart Pens/Cell Phones
2-AXIS
SENSOR
Factory Adjust
Offset & Gain
Y axis
Low Pass
Filter
A
OUTY
V
DD
Gnd
V
DA
MXA2500G/M FUNCTIONAL BLOCK DIAGRAM
Gaming
– Joystick/RF Interface/Menu Selection/Tilt Sensing
GPS
– Electronic compass tilt correction
Consumer
– LCD projectors, pedometers, blood pressure
Monitor, digital cameras
GENERAL DESCRIPTION
The MXA2500G/M is a low cost, dual axis accelerometer
fabricated on a standard, submicron CMOS process. It is a
complete sensing system with on-chip mixed mode signal
processing. The MXA2500G/M measures acceleration
with a full-scale range of
±1.7g
and a sensitivity of
500mV/g @5V at
25°C
. It can measure both dynamic
acceleration (e.g. vibration) and static acceleration (e.g.
gravity). The MXA2500G/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 of 50,000
g,
leading to significantly lower failure rate and lower loss
due to handling during assembly.
The MXA2500G/M provides two absolute analog outputs.
The typical noise floor is 0.2 mg/
Hz
allowing signals
below 1 milli-g to be resolved at 1 Hz bandwidth.
The
3dB rolloff of the device occurs at 17 Hz but is expandable
to >160 Hz (reference Application Note AN-00MX-003).
The MXA2500G/M is packaged in a hermetically sealed
LCC surface mount package (5 mm x 5 mm x 2 mm height)
and is operational over a -40
°C
to 105
°C(M)
and 0°C to
70°C(G) temperature range.
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 MXA2500G/M Rev.
E
Page 1 of 8
1/19/2005
MXA2500G/M SPECIFICATIONS
(Measurements @ 25°C, Acceleration = 0
g
unless otherwise noted; V
DD
, V
DA
= 5.0V unless
otherwise specified)
MXA2500G
Typ
MXA2500M
Typ
Parameter
SENSOR INPUT
Measurement Range
1
Nonlinearity
Alignment Error
2
Transverse Sensitivity
3
SENSITIVITY
Sensitivity, Analog Outputs at
pins
A
OUTX
and A
OUTY5
Change over Temperature
ZERO
g
BIAS LEVEL
0
g
Offset
5
0
g
Voltage
5
0
g
Offset over Temperature
NOISE PERFORMANCE
Noise Density, rms
Conditions
Each Axis
Best fit straight line
X Sensor to Y Sensor
Each Axis
Min
±1.7
Max
Min
±1.7
Max
Units
g
0.5
±1.0
±2.0
1.0
0.5
±1.0
±2.0
1.0
% of FS
degrees
%
475
-10
Each Axis
-0.1
1.20
Based on 500 mV/g
Without frequency
compensation
15
500
525
+8
475
-25
-0.1
1.20
500
525
+8
mV/g
%
g
V
mg/°C
mV/°C
mg/
Hz
Hz
Hz
V
mV/°K
V
mV/°C
µA
0.0
1.25
±1.5
±0.75
0.2
17
>160
1.25
5.0
2.5
0.1
+0.1
1.30
0.0
1.25
±1.5
±0.75
0.2
+0.1
1.30
0.4
19
15
0.4
19
FREQUENCY RESPONSE
3dB Bandwidth - uncompensated
3dB Bandwidth – compensated
4
TEMPERATURE OUTPUT
T
out
Voltage
Sensitivity
VOLTAGE REFERENCE
V
Ref
@3.0V-5.25V supply
Change over Temperature
Current Drive Capability
Source
SELF TEST
Continuous Voltage at A
OUTX
,
@5.0V Supply, output
A
OUTY
under Failure
rails to
supply voltage
Continuous Voltage at A
OUTX
,
@3.0V Supply, output
A
OUTY
under Failure
rails to
supply voltage
A
OUTX
and A
OUTY
OUTPUTS
Normal Output Range
@5.0V Supply
@3.0V Supply
Current
Source or sink, @
3.0V-5.25V supply
Turn-On Time
6
@5.0V Supply
@3.0V Supply
POWER SUPPLY
Operating Voltage Range
Supply Current
@ 5.0V
5
Supply Current
@ 3.0V
TEMPERATURE RANGE
Operating Range
NOTES
1
2
17
>160
1.25
5.0
2.5
0.1
1.15
4.6
2.4
1.35
5.4
2.65
100
1.15
4.6
2.4
1.35
5.4
2.65
100
5.0
3.0
5.0
3.0
V
V
0.1
0.1
160
300
3.0
2.5
3.0
0
5
4.9
2.9
100
0.1
0.1
160
300
4.9
2.9
100
V
V
µA
mS
mS
3.1
3.8
5.25
3.9
4.6
+70
3.0
2.5
3.0
-40
3.1
3.8
5.25
3.9
4.6
+105
V
mA
mA
°C
Guaranteed by measurement of initial offset and sensitivity.
Alignment error is specified as the angle between the true and indicated axis of
sensitivity.
3
Transverse sensitivity is the algebraic sum of the alignment and the inherent sensitivity
errors.
External circuitry is required to extend the 3dB bandwidth (ref. Application Note: AN-
00MX-003)
4
The device operates over a 3.0V to 5.25V supply range. Please note that sensitivity and
zero
g
bias level will be slightly different at 3.0V operation. For devices to be operated at
3.0V in production, they can be trimmed at the factory specifically for this lower supply
voltage operation, in which case the sensitivity and zero
g
bias level specifications on this
page will be met. Please contact the factory for specially trimmed devices for low supply
voltage operation.
5
Output settled to within
±17mg
.
MEMSIC MXA2500G/M Rev.
E
Page 2 of 8
1/19/2005
8
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage (V
DD
, V
DA
) ………………...-0.5 to +7.0V
Storage Temperature ……….…………-65°C to +150°C
Acceleration, constant…………….……………..50,000
g
Shock (Powered) , Half Sine
(shock rating limited by test
equipment, virtually unlimited by design)
Level (g)
Duration(ms)
3000
0.5
2000
1.0
1000
700
500
2.0
3.0
5.0
1
7
M E M S IC
X +g
6
2
3
5
4
Y +g
T o p V ie w
*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.
Figure 1:
Note -
The MEMSIC logo’s arrow indicates the +X
sensing direction of the device. The +Y sensing direction is
rotated 90° away from the +X direction following the right-hand
rule. Small circle indicates pin one(1).
Package Characteristics
Package
θ
JA
LCC-8
110°C/W
θ
JC
22°C/W
Device Weight
< 1 gram
Pin Description: LCC-8 Package
Pin
Name
Description
1
T
OUT
Temperature (Analog Voltage)
2
A
OUTY
Y-Axis Acceleration Signal
3
Gnd
Ground
4
V
DA
Analog Supply Voltage
5
A
OUTX
X-Axis Acceleration Signal
6
V
ref
2.5V Reference
7
Sck
Optional External Clock
8
V
DD
Digital Supply Voltage
Ordering Guide
Model
Package Style
MXA2500GL
LCC8
RoHS compliant
MXA2500GF
MXA2500ML
THEORY OF OPERATION
The MEMSIC device is a complete dual-axis acceleration
measurement system fabricated on a monolithic CMOS IC
process. The device operation is based on heat transfer by
natural convection and operates like other accelerometers
having a proof mass. The proof mass in the MEMSIC
sensor is a gas.
A single 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 (dual axis). 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. There are two identical
acceleration signal paths on the accelerometer, one to
measure acceleration in the x-axis and one to measure
acceleration in the y-axis. Please visit the MEMSIC
website at www.memsic.com for a picture/graphic
description of the free convection heat transfer principle
Temperature Range
0 to 70°C
0 to 70°C
-40 to 105°C
LCC8, Pb-free
LCC8
RoHS compliant
MXA2500MF
LCC8, Pb-free
-40 to 105°C
All parts are shipped in tape and reel packaging.
Caution:
ESD (electrostatic discharge) sensitive device.
MEMSIC MXA2500G/M Rev.
E
Page 3 of 8
1/19/2005
TYPICAL CHARACTERISTICS, % OF UNITS ( @ 25°C, Vdd = 5V , unless specified)
25%
20%
15%
10%
5%
0%
1.226
1.231
1.236
1.241
1.246
1.251
1.256
1.261
1.266
1.271
60%
50%
40%
30%
20%
10%
0%
1.214
1.222
1.229
1.237
1.244
1.252
1.260
1.267
1.275
1.275
513
Graph 1. Distribution of
Tout
(Volts)
25%
20%
15%
10%
5%
0%
2.406
2.431
2.456
2.481
2.506
2.531
2.556
2.581
2.606
2.631
60%
50%
40%
30%
20%
10%
0%
Graph 5. Distribution of 0g Offset
A
OUTX
(Volts)
1.214
1.222
1.229
1.237
1.244
1.252
1.260
1.267
Graph 2. Distribution of
Vref
(Volts)
35%
30%
25%
20%
15%
10%
5%
0%
2.733
2.863
2.993
3.123
3.253
3.383
3.513
3.643
3.773
3.903
25%
20%
15%
10%
5%
0%
Graph 6. Distribution of 0g Offset
A
OUTY
(Volts)
481
485
489
493
497
501
505
509
Graph 3. Distribution of
Idd
(mA)
40%
30%
20%
Graph 7. Distribution of
A
OUTX
Sensitivity (mV/g)
25%
20%
15%
10%
10%
0%
5%
0%
17
18
19
20
21
22
23
481
485
489
493
497
501
505
509
513
Graph 4. Distribution of Freq. Resp. (Hz)
Graph 8. Distribution of
A
OUTY
Sensitivity (mV/g)
MEMSIC MXA2500G/M Rev.
E
Page 4 of 8
1/19/2005
517
517
1.282
1.282
TYPICAL CHARACTERISTICS OVER TEMPERATURE ( 0°C to 70°C, Vdd = 5V , unless specified)
40%
35%
30%
25%
20%
15%
10%
5%
0%
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
milli-g / °C
100
80
60
40
20
0
-20
-40
-60
-80
-100
0°C
10°C 20°C 30°C 40°C 50°C 60°C 70°C
% OF UNITS
Graph 9. Distribution of
A
OUTX
0g offset over temperature
40%
35%
25%
20%
15%
10%
5%
0%
Graph 12. Examples of
A
OUTY
0g offset vs. temperature
8%
6%
4%
2%
0%
-2%
-4%
-6%
-8%
-10%
0°C
10°C 20°C 30°C 40°C 50°C 60°C 70°C
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
milli-g / °C
Graph 10. Distribution of
A
OUTY
0g offset over temperature
100
80
60
40
20
0
-20
-40
-60
-80
-100
0°C
10°C 20°C 30°C 40°C 50°C 60°C 70°C
3.0
Graph 13. Examples of
A
OUTX
Sensitivity change over temperature
8%
6%
% Sensitivity change
% Sensitivity change
30%
% OF UNITS
0g offset (milli-g)
4%
2%
0%
-2%
-4%
-6%
-8%
-10%
0°C
10°C
20°C
30°C
40°C
50°C
60°C
70°C
Graph 11. Examples of
A
OUTX
0g offset vs. temperature
0g offset (milli-g)
Graph 14. Examples of
A
OUTY
Sensitivity change over temperature
MEMSIC MXA2500G/M Rev.
E
Page 5 of 8
1/19/2005
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