MPX2102

Sensors

4

Freescale Semiconductor

LINEARITY

Linearity refers to how well a transducer's output follows

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.

Freescale’s specified pressure sensor linearities are based

on the end point straight line method measured at the

midrange pressure.

Figure 2. Linearity Specification Comparison

ON-CHIP TEMPERATURE COMPENSATION AND CALIBRATION

Figure 3 shows the output characteristics of the MPX2102/

MPXV2102G series at 25°C. The output is directly

proportional to the differential pressure and is essentially a

straight line.

The effects of temperature on Full Scale Span and Offset

are very small and are shown under Operating

Characteristics.

Figure 3. Output vs. Pressure Differential

Figure 4. Cross Sectional Diagrams (Not to Scale)

Figure 4 illustrates the absolute sensing configuration

(right) and 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 MPX2102/MPXV2102G 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.

Least

Square

Deviation

Pressure (% Fullscale)

0

50

100

End Point Straight

Line Fit

Exaggerated

Performance

Curve

Least Squares Fit

Offset

Straight Line

Deviation

TA = 25°C

MPX2102

P1 > P2

40

35

30

25

20

15

10

5

0

-5

TYP

MAX

MIN

Span

Range

(TYP)

Offset

(TYP)

025

50

75

100

kPa

PSI

3.62

7.25

10.88

14.5

Lead Frame

Wire Bond

Differential/Gauge

Die

Silcone Gel

Die Coat

Differential/Gauge

P2

Die

Bond

Epoxy

Case

Stainless Steel

Metal Cover

P1

Silicone Gel

Die Coat

Absolute

Die

P1

Metal Cover

Epoxy

Case

Absolute Element

P2

Lead Frame

Wire Bond

Die

Bond

Stainless Steel

Element