
3–169
Motorola Sensor Device Data
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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 cal-
culations 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
R
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 MPXM2202 series at 25
°
C. The output
is directly proportional to the differential pressure and is es-
sentially a straight line.
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.
Figure 3. Output versus Pressure Differential
40
35
30
25
20
15
10
5
0
–50
kPa
PSI
50
7.25
100
14.5
150
21.75
200
29
PRESSURE
O
SPAN
RANGE
(TYP)
OFFSET
VS = 10 Vdc
TA = 25
°
C
P1 > P2
25
75
125
175
MAX
TYP
MIN
ORDERING INFORMATION
Device Type/Order No.
Options
Case Type
MPXM2202D
Non–ported
1320
MPXM2202DT1
Non–ported, Tape and Reel
1320
MPXM2202GS
Ported
1320A
MPXM2202GST1
Ported, Tape and Reel
1320A
MPXM2202A
Non–ported
1320
MPXM2202AT1
Non–ported, Tape and Reel
1320
MPXM2202AS
Ported
1320A
MPXM2202AST1
Ported, Tape and Reel
1320A
F
Freescale Semiconductor, Inc.
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