MPX2050 SERIES

3

Motorola Sensor Device Data

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. Motorola’s

specified pressure sensor linearities are based on the end

point straight line method measured at the midrange pres-

sure.

Figure 2. Linearity Specification Comparison

LEAST

SQUARE

DEVIATION

PRESSURE (% FULLSCALE)

0

50

100

END POINT

STRAIGHT LINE FIT

EXAGGERATED

PERFORMANCE

CURVE

LEAST SQUARES FIT

STRAIGHT LINE

DEVIATION

OFFSET

ON–CHIP TEMPERATURE COMPENSATION and CALIBRATION

Figure 3 shows the minimum, maximum and typical output

characteristics of the MPX2050 series at 25

°C. The output is

directly proportional to the differential pressure and is essen-

tially a straight line.

The effects of temperature on Full–Scale Span and Offset

are very small and are shown under Operating Characteris-

tics.

Figure 3. Output versus Pressure Differential

Figure 4. Cross–Sectional Diagram (not to scale)

kPa

PSI

40

35

30

25

15

10

5

0

-5

0

12.5

1.8

25

3.6

37.5

5.4

50

7.25

SPAN

RANGE

(TYP)

OFFSET

(TYP)

20

SILICONE

DIE COAT

WIRE BOND

LEAD FRAME

DIE

STAINLESS STEEL

METAL COVER

EPOXY

CASE

RTV DIE

BOND

P1

P2

MAX

TYP

MIN

MPX2050

P1 > P2

Figure 4 illustrates 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 MPX2050 series pressure sensor operating charac-

teristics 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 perfor-

mance and long term reliability. Contact the factory for in-

formation regarding media compatibility in your application.

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

ARCHIVED BY FREESCALE SEMICONDUCTOR, INC. 2005