MPX2053
Sensors
5 Freescale Semiconductor, Inc.
Pressure
LINEARITY
Linearity refers to how well a transducer's output follows
the equation: V
out
= V
off
+ sensitivity x P over the operating
pressure range. There are two basic methods for calculating
nonlinearity: (1) end point straight line fit (see Figure 3) 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. The
specified pressure sensor linearities are based on the end
point straight line method measured at the midrange
pressure.
Figure 3. Linearity Specification Comparison
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 MPX2053 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.
Refer to application note AN3728, for more information
regarding media compatibility.
Figure 4. Unibody Package — Cross-Sectional Diagram (Not to Scale)
Relative Voltage Output
Pressure (% Full scale)
0 50 100
End Point
Straight Line Fit
Exaggerated
Performance
Least Squares Fit
Straight Line
OFFSET
Least
Square
Deviation
Silicone
Die Coat Die
P1
P2
Wire Bond
Lead Frame
RTV Die
Bond
Epoxy
Case
Stainless Steel
Metal Cover
