Sensors

Freescale Semiconductor

3

MPXM2010

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.

Freescale's specified pressure sensor linearities are based

on the end point straight line method measured at the

midrange pressure.

Characteristic

Symbol

Min

Typ

Max

Unit

1. 1.0 kPa (kiloPascal) equals 0.145 psi.

0—

10

kPa

2. Device is ratiometric within this specified excitation range. Operating the device above the specified excitation range may induce additional

error due to device self-heating.

—10

16

Vdc

Supply Current

—6.0

—

mAdc

the minimum rated pressure.

24

25

26

mV

–1.0

—

1.0

mV

Sensitivity

∆V/∆P—

2.5

—

mV/kPa

5. Accuracy (error budget) consists of the following:

• Linearity:

Output deviation from a straight line relationship with pressure, using end point method, over the

specified pressure range.

• Temperature Hysteresis:

Output deviation at any temperature within the operating temperature range, after the temperature is

cycled to and from the minimum or maximum operating temperature points, with zero differential

pressure applied.

• Pressure Hysteresis:

Output deviation at any pressure within the specified range, when this pressure is cycled to and from

the minimum or maximum rated pressure, at 25

°C.

• TcSpan:

Output deviation at full rated pressure over the temperature range of 0 to 85

°C, relative to 25°C.

• TcOffset:

Output deviation with minimum rated pressure applied, over the temperature range of 0 to 85

°C,

relative to 25

°C.

—

–1.0

—

1.0

——

±0.1

—

°C to +125°C)

——

±0.5

—

–1.0

—

1.0

–1.0

—

1.0

mV

Input Impedance

1000

—

2550

Ω

Output Impedance

1400

—

3000

Ω

6. Response Time is defined as the time for the incremental change in the output to go from 10% to 90% of its final value when subjected to

a specified step change in pressure.

—1.0

—

ms

Warm-Up

——

20

—

ms

7. Offset stability is the product's output deviation when subjected to 1000 hours of Pulsed Pressure, Temperature Cycling with Bias Test.

——

±0.5

—