MPX2100 MPX2101 SERIES

3

Motorola Sensor Device Data

LINEARITY

Linearity refers to how well a transducer’s output follows

the equation: Vout = Voff + sensitivity x P over the operating

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

pressure.

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 output characteristics of the MPX2100

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 Characteris-

tics.

Figure 3. Output versus Pressure Differential

Figure 4. Cross–Sectional Diagrams (Not to Scale)

kPa

PSI

40

35

30

25

15

10

5

0

–5

025

3.62

50

7.25

75

10.87

100

14.5

SPAN

RANGE

(TYP)

OFFSET

(TYP)

20

TYP

MIN

VS = 10 Vdc

TA = 25°C

P1 > P2

MAX

SILICONE GEL

DIE COAT

WIRE BOND

LEAD FRAME

DIFFERENTIAL/GAUGE

DIE

STAINLESS STEEL

METAL COVER

EPOXY

CASE

DIFFERENTIAL/GAUGE ELEMENT

DIE

BOND

SILICONE GEL

DIE COAT

WIRE BOND

LEAD FRAME

ABSOLUTE

DIE

STAINLESS STEEL

METAL COVER

EPOXY

CASE

DIE

BOND

ABSOLUTE ELEMENT

P1

P2

P1

P2

Figure 4 illustrates the absolute sensing configuration

(right) and the differential or gauge configuration in the basic

chip carrier (Case 344–15). 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 MPX2100 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.