MPX4250D SERIES

3

Motorola Sensor Device Data

Figure 2. Cross–Sectional Diagram

(Not to Scale)

µ PROCESSOR

A/D

51 k

50 pF

MPX4250D

OUPUT

(PIN 1)

Figure 3. Typical Decoupling Filter for Sensor to

Microprocessor Interface

FLUORO SILICONE

DIE COAT

WIRE BOND

LEAD

FRAME

DIE

STAINLESS STEEL

METAL COVER

RTV DIE

BOND

P1

P2

EPOXY CASE

Figure 2 illustrates the Differential/Gauge Pressure Sens-

ing Chip in the basic chip carrier (Case 867). A fluorosilicone

gel isolates the die surface and wire bonds from the environ-

ment, while allowing the pressure signal to be transmitted to

the sensor diaphragm.

The MPX4250D 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 performance

and long–term reliability. Contact the factory for information

regarding media compatibility in your application.

Figure 3 shows a typical decoupling circuit for interfacing

the integrated sensor to the A/D input of a microprocessor.

Proper decoupling of the power supply is recommended.

Figure 4 shows the sensor output signal relative to pres-

sure input. Typical, minimum, and maximum output curves

are shown for operation over a temperature range of 0

° to

85

°C using the decoupling circuit below. (The output will sat-

urate outside of the specified pressure range.)

0

5.0

4.5

4.0

3.5

3.0

PRESSURE in kPa

MAX

MIN

2.5

2.0

1.5

1.0

0.5

Figure 4. Output versus Differential Pressure

TYP

TRANSFER FUNCTION:

Vout = VS* (0.00369*P + 0.04) ± Error

VS = 5.1 Vdc

TEMP = 0 to 85

°C