Pressure
Freescale Semiconductor
+
MPX2050
Rev 9, 10/2008
50 kPa On-Chip Temperature
Compensated and Calibrated
Silicon Pressure Sensors
MPX2050
Series
0 to 50 kPa (0 to 7.25 psi)
40 mV Full Scale Span
(Typical)
The MPX2050 series devices are silicon piezoresistive pressure sensors
providing a highly accurate and linear voltage output, directly proportional to the
applied pressure. The sensor is a single, monolithic silicon diaphragm with the
strain gauge and a thin-film resistor network integrated on-chip. The chip is laser
trimmed for precise span and offset calibration and temperature compensation.
Application Examples
Features
•
•
•
•
•
•
Temperature Compensated Over 0°C to +85°C
Unique Silicon Shear Stress Strain Gauge
Easy to Use Chip Carrier Package Options
Ratiometric to Supply Voltage
Differential and Gauge Options
±0.25%
Linearity
•
•
•
•
•
•
Pump/Motor Controllers
Robotics
Level Indicators
Medical Diagnostics
Pressure Switching
Non-Invasive Blood Pressure
ORDERING INFORMATION
Package
Case
Options
No.
Unibody Package (MPX2050 Series)
MPX2050D
Tray
344
MPX2050GP
Tray
344B
Device Name
MPX2050DP
MPX2050GSX
Tray
Tray
344C
344F
None
# of Ports
Single
Dual
Gauge
Pressure Type
Differential
Absolute
Device Marking
MPX2050D
MPX2050GP
MPX2050DP
MPX2050D
•
•
•
•
PACKAGES
•
•
•
•
MPX2050D
CASE 344-15
MPX2050GP
CASE 344B-01
MPX2050DP
CASE 344C-01
MPX2050GSX
CASE 344F-01
© Freescale Semiconductor, Inc., 2002, 2008. All rights reserved.
Pressure
Figure 1
shows a block diagram of the internal circuitry on the stand-alone pressure sensor chip.
V
S
3
Thin Film
Temperature
Compensation
and Calibration
Circuitry
2
Sensing
Element
+V
OUT
4 -V
OUT
1
GND
Figure 1. Temperature Compensated Pressure Sensor Schematic
Voltage Output versus Applied Differential Pressure
The differential voltage output of the sensor is directly
proportional to the differential pressure applied.
The output voltage of the differential or gauge sensor
increases with increasing pressure applied to the pressure
side (P1) relative to the vacuum side (P2). Similarly, output
voltage increases as increasing vacuum is applied to the
vacuum side (P2) relative to the pressure side (P1).
MPX2050
2
Sensors
Freescale Semiconductor
Pressure
Operating Characteristics
Table 1. Operating Characteristics
(V
S
= 10 Vdc, T
A
= 25°C unless otherwise noted, P1 > P2)
Characteristics
Pressure Range
(1)
Supply Voltage
(2)
Supply Current
Full Scale Span
(3)
Offset
(4)
Sensitivity
Linearity
(5)
Pressure Hysteresis
(5)
(0 to 50 kPa)
Temperature Hysteresis
(5)
(-40°C to +125°C)
Temperature Effect on Full Scale Span
(5)
Temperature Effect on Offset
(5)
Input Impedance
Output Impedance
Response Time
(6)
(10% to 90%)
Warm-Up
Offset Stability
(7)
1. 1.0 kPa (kiloPascal) equals 0.145 psi.
2. Device is ratiometric within this specified excitation range. Operating the device above the specified excitation range may induce additional
error due to device self-heating.
3. Full Scale Span (V
FSS
) is defined as the algebraic difference between the output voltage at full rated pressure and the output voltage at the
minimum rated pressure.
4. Offset (V
off
) is defined as the output voltage at the minimum rated pressure.
5. Accuracy (error budget) consists of the following:
Linearity:Output deviation from a straight line relationship with pressure, using end point method, over the specified pressure range.
Temperature Hysteresis:Output deviation at any temperature within the operating temperature range, after the temperature is cycled to and
from the minimum or maximum operating temperature points, with zero differential pressure applied.
Pressure Hysteresis:Output deviation at any pressure within the specified range, when this pressure is cycled to and from the minimum or
maximum rated pressure, at 25°C.
TcSpan:Output deviation at full rated pressure over the temperature range of 0 to 85°C, relative to 25°C.
TcOffset:Output deviation with minimum rated pressure applied, over the temperature range of 0 to 85°C, relative to 25°C.
6. Response Time is defined as the time for the incremental change in the output to go from 10% to 90% of its final value when subjected to a
specified step change in pressure.
7. Offset stability is the product's output deviation when subjected to 1000 hours of Pulsed Pressure, Temperature Cycling with Bias Test.
Symbol
P
OP
V
S
I
o
V
FSS
V
off
ΔV/ΔP
—
—
—
TCV
FSS
TCV
off
Z
in
Z
out
t
R
—
—
Min
0
—
—
38.5
-1.0
—
-0.25
—
—
-1.0
-1.0
1000
1400
—
—
—
Typ
—
10
6.0
40
—
0.8
—
±0.1
±0.5
-
-
-
-
1.0
20
±0.5
Max
50
16
—
41.5
1.0
—
0.25
—
—
1.0
1.0
2500
3000
—
—
—
Unit
kPa
Vdc
mAdc
mV
mV
mV/kPa
%V
FSS
%V
FSS
%V
FSS
%V
FSS
mV
Ω
Ω
ms
ms
%V
FSS
MPX2050
Sensors
Freescale Semiconductor
3
Pressure
Maximum Ratings
Table 2. Maximum Ratings
(1)
Rating
Maximum Pressure (P1 > P2)
Storage Temperature
Operating Temperature
Symbol
P
max
T
stg
T
A
Value
200
-40 to +125
-40 to +125
Unit
kPa
°C
°C
1. Exposure beyond the specified limits may cause permanent damage or degradation to the device.
LINEARITY
Linearity refers to how well a transducer's output follows
the equation: V
out
= V
off
+ sensitivity x P over the operating
pressure range. There are two basic methods for calculating
nonlinearity: (1) end point straight line fit (see
Figure 2)
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 “worst 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.
Least Squares Fit
Exaggerated
Performance
Curve
Least
Square
Deviation
Relative Voltage Output
Straight Line
Deviation
End Point
Straight Line Fit
Offset
0
50
Pressure (% Fullscale)
100
Figure 2. Linearity Specification Comparison
MPX2050
4
Sensors
Freescale Semiconductor
Pressure
On-Chip Temperature Compensation and Calibration
Figure 3
shows the minimum, maximum and typical output
characteristics of the MPX2050 series at 25°C. The output is
directly proportional to the differential pressure and is
essentially a straight line.
40
35
Output (mVdc)
30
25
20
15
10
5
0
-5
kPa 0
PSI
Offset
(Typ)
MIN
V
S
= 10 Vdc
T
A
= 25°C
MPX2050
P1 > P2
MAX
The effects of temperature on Full-Scale Span and Offset
are very small and are shown under Operating
Characteristics.
TYP
Span
Range
(Typ)
12.5
1.8
25
3.6
37.5
5.4
50
7.25
Figure 3. Output versus Pressure Differential
Silicone
Die Coat
Wire Bond
Die
P1
Stainless Steel
Metal Cover
Epoxy
Case
Lead Frame
P2
RTV Die
Bond
Figure 4. Cross-Sectional Diagram (not to scale)
Figure 4
illustrates the differential or gauge configuration
in the basic chip carrier (Case 344). A silicone gel isolates the
die surface and wire bonds from the environment, while
allowing the pressure signal to be transmitted to the silicon
diaphragm.
The MPX2050 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
performance and long term reliability. Contact the factory for
information regarding media compatibility in your application.
MPX2050
Sensors
Freescale Semiconductor
5
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