Pressure
Freescale Semiconductor
+
MPX4250A
Rev 7, 1/2009
Integrated Silicon Pressure Sensor
Manifold Absolute Pressure Sensor
On-Chip Signal Conditioned,
Temperature Compensated and
Calibrated
MPX4250A
Series
20 to 250 kPa (2.9 to 36.3 psi)
0.2 to 4.9 V Output
The MPX4250A series Manifold Absolute Pressure (MAP) sensor for
engine control is designed to sense absolute air pressure within the intake
manifold. This measurement can be used to compute the amount of fuel
required for each cylinder.
The MPX4250A series piezoresistive transducer is a state-of-the-art
monolithic silicon pressure sensor designed for a wide range of applications,
particularly those employing a microcontroller or microprocessor with A/D
inputs. This transducer combines advanced micromachining techniques, thin-
film metallization and bipolar processing to provide an accurate, high-level
analog output signal that is proportional to the applied pressure. The small
form factor and high reliability of on-chip integration make the Freescale
sensor a logical and economical choice for the automotive system engineer.
Features
•
•
•
•
•
•
•
Application Examples
•
•
Turbo Boost Engine Control
Ideally Suited for Microprocessor or
Microcontroller-Based Systems
1.5% Maximum Error Over 0° to 85°C
Specifically Designed for Intake Manifold Absolute Pressure Sensing in Engine Control Systems
Patented Silicon Shear Stress Strain Gauge
Temperature Compensated Over -40° to +125°C
Offers Reduction in Weight and Volume Compared to Existing Hybrid Modules
Durable Epoxy Unibody Element or Thermoplastic Small Outline, Surface Mount Package
Ideal for Non-Automotive Applications
ORDERING INFORMATION
Package
Case
Options
No.
Small Outline Package (MPXA4250A Series)
MPXA4250A6U
Rail
482
MPXA4250AC6U
Rail
482A
Device Name
MPXA4250AC6T1
Tape and Reel
Unibody Package (MPX4250A Series)
MPX4250A
Tray
MPX4250AP
Tray
482A
867
867B
None
# of Ports
Single
Dual
Gauge
Pressure Type
Differential Absolute
Device Marking
MPXA4250A
MPXA4250A
MPXA4250A
MPX4250A
MPX4250A
•
•
•
•
•
•
•
•
•
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UNIBODY PACKAGES
SMALL OUTLINE PACKAGES
MPXA4250A6U
CASE 482-01
MPXA4250AC6U/C6T1
CASE 482A-01
MPX4250A
CASE 867-08
MPX4250AP
CASE 867B-04
© Freescale Semiconductor, Inc., 2006-2009. All rights reserved.
Pressure
Operating Characteristics
Table 1. Operating Characteristics
(V
S
= 5.1 V
DC
, T
A
= 25°C unless otherwise noted, P1 > P2, Decoupling circuit shown in
Figure 3
required to meet electrical specifications.)
Characteristic
Differential Pressure Range
(1)
Supply Voltage
(2)
Supply Current
Minimum Pressure Offset
(3)
@ V
S
= 5.1 Volts
Full Scale Output
(4)
@ V
S
= 5.1 Volts
Full Scale Span
(5)
@ V
S
= 5.1 Volts
Accuracy
(6)
Sensitivity
Response Time
(7)
Output Source Current at Full Scale Output
Warm-Up Time
(8)
Offset Stability
(9)
1. 1.0 kPa (kiloPascal) equals 0.145 psi.
2. Device is ratiometric within this specified excitation range.
3. Offset (V
OFF
) is defined as the output voltage at the minimum rated pressure.
4. Full Scale Output (V
FSO
) is defined as the output voltage at the maximum or full rated pressure.
5. 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.
6. Accuracy (error budget) consists of the following:
Linearity:
Temperature Hysteresis:
Pressure Hysteresis:
TcSpan:
TcOffset:
Variation from Nominal:
Output deviation at any temperature from a straight line relationship with pressure over the specified pressure
range.
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.
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.
Output deviation over the temperature range of 0° to 85°C, relative to 25°C.
Output deviation with minimum rated pressure applied, over the temperature range of 0° to 85°C, relative to 25°C.
The variation from nominal values, for Offset or Full Scale Span, as a percent of VFSS, at 25°C.
(0 to 85°C)
Symbol
P
OP
V
S
I
O
V
OFF
Min
20
4.85
—
0.133
Typ
—
5.1
7.0
0.204
Max
250
5.35
10
0.274
Units
kPa
V
DC
mAdc
V
DC
(0 to 85°C)
V
FSO
4.826
4.896
4.966
V
DC
(0 to 85°C)
V
FSS
—
4.692
—
V
DC
(0 to 85°C)
—
ΔV/ΔΡ
t
R
I
O
+
—
—
—
—
—
—
—
—
—
20
1.0
0.1
20
±0.5
±1.5
—
—
—
—
—
%V
FSS
mV/kPa
msec
mAdc
msec
%V
FSS
7. Response Time is defined as the time form 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.
8. Warm-up Time is defined as the time required for the product to meet the specified output voltage after the pressure is stabilized.
9. Offset stability is the product’s output deviation when subjected to 1000 hours of Pulsed Pressure, Temperature Cycling with Bias Test.
MPX4250A
2
Sensors
Freescale Semiconductor
Pressure
Maximum Ratings
Table 2. Maximum Ratings
(1)
Rating
Maximum Pressure
(2)
(P1 > P2)
Storage Temperature
Operating Temperature
1. TC = 25°C unless otherwise noted.
2. Exposure beyond the specified limits may cause permanent damage or degradation to the device.
Symbol
P
MAX
T
STG
T
A
Value
1000
-40 to +125
-40 to +125
Unit
kPa
°C
°C
Figure 1
shows a block diagram of the internal circuitry integrated on a pressure sensor chip.
3 (Unibody)
2 (Small Outline Package)
V
S
Sensing
Element
Thin Film
Temperature
Compensation
and
Gain Stage #1
Gain Stage #2
and
Ground
Reference
Shift Circuitry
V
OUT
1 (Unibody)
4 (Small Outline Package)
GND
2 (Unibody)
3 (Small Outline Package)
Pins 4, 5, and 6 are NO CONNECTS
for unibody package devices.
Pins 1, 5, 6, 7, and 8 are NO CONNECTS
for small outline package devices.
Figure 1. Fully Integrated Pressure Sensor Schematic
for Unibody Package and Small Outline Package
MPX4250A
Sensors
Freescale Semiconductor
3
Pressure
On-chip Temperature Compensation and Calibration
Figure 2
illustrates the absolute pressure sensing chip in
the basic chip carrier (Case 867). A fluorosilicone gel isolates
the die surface and wire bonds from the environment, while
allowing the pressure signal to be transmitted to the sensor
diaphragm.
The MPX4250A 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.
.
Fluorosilicone
Die Coat
Wire Bond
Stainless Steel
Metal Cover
P1
Epoxy
Case
Contact the factory for information regarding media
compatibility in your application.
Figure 3
shows the recommended decoupling circuit for
interfacing the output of the integrated sensor to the A/D input
of a microprocessor or microcontroller.
Figure 4
shows the sensor output signal relative to
pressure input. Typical, minimum, and maximum output
curves are shown for operation over temperature range of 0°
to 85°C using the decoupling circuit shown in
Figure 3.
The
output will saturate outside of the specified pressure range.
Die
Lead Frame
Sealed Vacuum Reference
P2
RTV Die
Bond
Figure 2. Cross Sectional Diagram (not to scale)
+5.1
V
Vout
Vs
IPS
OUTPUT
1.0
μF
0.01
μF
GND
470 pF
Figure 3. Recommended Power Supply Decoupling and Output Filtering
(For additional output filtering, please refer to Application Note AN1646)
5.0
4.5
4.0
3.5
Output (Volts)
3.0
2.5
2.0
1.5
1.0
0.5
0
0
10
20
30
40
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
200
210
220
230
240
250
260
Pressure (ref: to sealed vacuum) in kPa
MIN
Transfer Function:
V
OUT
= V
s
* (0.004 x P-0.04) ± Error
V
S
= 5.1 Vdc
TEMP = 0 to 85°C
MAX
TYP
Figure 4. Output versus Absolute Pressure
MPX4250A
4
Sensors
Freescale Semiconductor
Pressure
Transfer Function
Nominal Transfer Value:
V
OUT
= V
S
(P
×
0.004 - 0.04)
± (Pressure Error
×
Temp. Factor
×
0.004
×
V
S
)
V
S
= 5.1 V ± 0.25 V
DC
Temperature Error Band
4.0
3.0
Temperature
Error
Factor
2.0
1.0
0.0
-40
-20
0
20
40
60
80
100
120
140
Temperature in C°
NOTE: The Temperature Multiplier is a linear response from 0× to -40°C and from 85° to 125°C.
Temp
- 40
0 to 85
+125
Multiplier
3
1
3
Pressure Error Band
5.0
4.0
3.0
2.0
1.0
0
-1.0
-2.0
-3.0
-4.0
-5.0
Pressure
Error
(kPa)
0
25
50
75 100 125 150 175 200 225 250
Pressure
(kPa)
Pressure
20 to 250 kPa
Error (Max)
±3.45 (kPa)
MPX4250A
Sensors
Freescale Semiconductor
5
