Motorola MPx200 MPX200 Leaflet
Product codes
MPX200
3
Motorola Sensor Device Data
LINEARITY
Linearity refers to how well a transducer’s output follows
the equation: Vout = Voff + sensitivity x P over the operating
pressure range (see Figure 2). There are two basic methods
for calculating nonlinearity: (1) end point straight line fit or (2)
a least squares best line fit. While a least squares fit gives
the “best case” linearity error (lower numerical value), the
calculations required are burdensome.
pressure range (see Figure 2). There are two basic methods
for calculating nonlinearity: (1) end point straight line fit or (2)
a least squares best line fit. While a least squares fit gives
the “best case” linearity error (lower numerical value), the
calculations required are burdensome.
Conversely, an end point fit will give the “worse case” error
(often more desirable in error budget calculations) and the
calculations are more straightforward for the user. Motorola’s
specified pressure sensor linearities are based on the end
point straight line method measured at the midrange
pressure.
calculations are more straightforward for the user. Motorola’s
specified pressure sensor linearities are based on the end
point straight line method measured at the midrange
pressure.
TEMPERATURE COMPENSATION
Figure 3 shows the typical output characteristics of the
MPX200 series over temperature. The output is directly pro-
portional to the pressure and is essentially a straight line.
portional to the pressure and is essentially a straight line.
The X–ducer piezoresistive pressure sensor element is a
semiconductor device which gives an electrical output signal
proportional to the pressure applied to the device. This de-
vice uses a unique transverse voltage diffused semiconduc-
tor strain gauge which is sensitive to stresses produced in a
thin silicon diaphragm by the applied pressure.
vice uses a unique transverse voltage diffused semiconduc-
tor strain gauge which is sensitive to stresses produced in a
thin silicon diaphragm by the applied pressure.
Because this strain gauge is an integral part of the silicon
diaphragm, there are no temperature effects due to differ-
ences in the thermal expansion of the strain gauge and the
diaphragm, as are often encountered in bonded strain gauge
pressure sensors. However, the properties of the strain
gauge itself are temperature dependent, requiring that the
device be temperature compensated if it is to be used over
an extensive temperature range.
ences in the thermal expansion of the strain gauge and the
diaphragm, as are often encountered in bonded strain gauge
pressure sensors. However, the properties of the strain
gauge itself are temperature dependent, requiring that the
device be temperature compensated if it is to be used over
an extensive temperature range.
Temperature compensation and offset calibration can be
achieved rather simply with additional resistive components
or by designing your system using the MPX2200 series
sensors.
or by designing your system using the MPX2200 series
sensors.
Several approaches to external temperature compensa-
tion over both – 40 to +125
°
C and 0 to + 80
°
C ranges are
presented in Motorola Applications Note AN840.
Figure 2. Linearity Specification Comparison
Figure 3. Output versus Pressure Differential
Figure 4. Cross–Sectional Diagrams (Not to Scale)
70
60
50
40
30
20
10
0
0
20
40
60 80
100 120 140 160 180 200
4.0
8.0
12
16
20
24
28
30
PRESSURE DIFFERENTIAL
PSI
kPa
kPa
OUTPUT
(mVdc)
OFFSET
(TYP)
– 40
°
C
+25
°
C
+125
°
C
SPAN
RANGE
(TYP)
VS = 3.0 Vdc
P1 > P2
ÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉ
SILICONE GEL
DIE COAT
WIRE BOND
LEAD FRAME
DIFFERENTIAL/GAUGE
DIE
DIE
STAINLESS STEEL
METAL COVER
EPOXY
CASE
DIFFERENTIAL/GAUGE ELEMENT
DIE
BOND
ÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉ
SILICONE GEL
DIE COAT
WIRE BOND
LEAD FRAME
ABSOLUTE
DIE
STAINLESS STEEL
METAL COVER
EPOXY
CASE
DIE
BOND
ABSOLUTE ELEMENT
P1
P2
P1
P2
OFFSET
(VOFF)
70
OUTPUT
(mVdc)
60
50
40
30
20
10
0
0
MAX
POP
SPAN
(VFSS)
PRESSURE (kPA)
ACTUAL
THEORETICAL
LINEARITY
Figure 4 illustrates the absolute sensing configuration
(right) and the differential or gauge configuration in the basic
chip carrier (Case 344–15). A silicone gel isolates the die
surface and wire bond from the environment, while allowing
the pressure signal to be transmitted to the silicon dia-
phragm. The MPX200 series pressure sensor operating
chip carrier (Case 344–15). A silicone gel isolates the die
surface and wire bond from the environment, while allowing
the pressure signal to be transmitted to the silicon dia-
phragm. The MPX200 series pressure sensor operating
characteristics and internal reliability and qualification tests
are based on use of dry air as the pressure media. Media
other than dry air may have adverse effects on sensor perfor-
mance and long term reliability. Contact the factory for in-
formation regarding media compatibility in your application.
are based on use of dry air as the pressure media. Media
other than dry air may have adverse effects on sensor perfor-
mance and long term reliability. Contact the factory for in-
formation regarding media compatibility in your application.