MPX4115A
Sensors
Freescale Semiconductor 5
Pressure
On-chip Temperature Compensation and Calibration
Figure 2 illustrates an absolute sensing chip in the basic
chip carrier (Case 867) and the small outline chip carrier
(Case 482). 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
MPX4115A 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. Proper decoupling of
the power supply is recommended.
Figure 4 shows the sensor output signal relative to
pressure input. Typical, minimum, and maximum output
curves are shown for operation over a 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 output filtering recommendations, refer to Application Note AN1646.)
Figure 4. Output versus Absolute Pressure
Fluoro Silicone
Gel Die Coat
Die
P1
Metal Cover
Epoxy Plastic
Case
Absolute Element
P2
Lead Frame
Wire Bond
Die
Bond
Stainless Steel
Sealed Vacuum Reference
P1
Fluoro Silicone
Gel Die Coat
Die
Steel Cap
Stainless Steel
Thermoplastic
Case
Die
Bond
Absolute Element
Sealed Vacuum Reference
Lead Frame
Wire Bond
+5.1 V
1.0 μF
0.01 μF
470 pFGND
V
s
V
out
IPS
Output
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
TRANSFER FUNCTION:
V
out
= V
s
* (.009*P-.095) ± Error
V
S
= 5.1 Vdc
TEMP = 0 to 85°C
Pressure (ref. to sealed vacuum) in kPa
TYP
MAX
MIN
5.0
4.5
3.5
4.0
3.0
2.5
2.0
1.5
1.0
0
0.5
Output (Volts)
