Datasheet

MPX4250A
Sensors
4 Freescale Semiconductor
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.
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.
.
Figure 2. Cross Sectional Diagram (not to scale)
Figure 3. Recommended Power Supply Decoupling and Output Filtering
(For additional output filtering, please refer to Application Note AN1646)
Figure 4. Output versus Absolute Pressure
Fluorosilicone
Die Coat
Wire Bond
RTV Die
Bond
Die
P1
P2
Epoxy
Case
Lead Frame
Sealed Vacuum Reference
Stainless Steel
Metal Cover
1.0 μF
470 pF
Vs
+5.1 V
0.01 μF
GND
Vout
IPS
OUTPUT
Output (Volts)
5.0
4.5
4.0
3.5
3.0
MAX
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
MIN
TYP
Pressure (ref: to sealed vacuum) in kPa
Transfer Function:
V
OUT
= V
s
* (0.004 x P-0.04) ± Error
V
S
= 5.1 Vdc
TEMP = 0 to 85°C