MPX2202

Sensors

4

Freescale Semiconductor

LINEARITY

Linearity refers to how well a transducer's output follows

pressure range. There are two basic methods for calculating

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 MPX2202/

MPXV2202G 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 versus Pressure Differential

Least

Square

Deviation

Pressure (% Fullscale)

0

50

100

End Point Straight

Line Fit

Exaggerated

Performance

Curve

Least Squares Fit

Straight Line

Deviation

Offset

VS = 10 Vdc

TA = 25°C

P1 > P2

40

35

30

25

20

15

10

5

0

-5

TYP

MAX

MIN

Span

Range

(TYP)

Offset

(TYP)

0

50

100

150

200

kPa

PSI

7.25

14.5

21.75

29

175

125

75

25

Pressure