MPX2053

Sensors

5

Freescale Semiconductor, Inc.

Pressure

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 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)

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