MPXM2102AS datasheet(353/670 Pages) MOTOROLA

353 / 670 page

AN1097

3–207

Motorola Sensor Device Data

www.motorola.com/semiconductors

When the tolerance of the system has to be in the range of

±1%, the designer should provide only one calibration

procedure which sets the Full Scale Output (counts) at 25

°C

100 kPa or under the local atmospheric pressure conditions.

PRESSURE

SENSOR

SYSTEM

MPX2100AP

MC74HC4053

MC33078

1/3

MC74HC4053

+ 5 V

0 V

I/O

MC68HC05B6

CH1

VRL

VSS

VRH

VDD

–

Figure 11. One Channel Input and Two Output Ports are used by the MCU

–

Due to the high impedance input of the A/D converter of the

MC68HC05B6

MCU,

another

configuration

may

implemented which uses only one channel input as shown in

Figure 11. It is interesting to notice that practically any dual op

amp may be used to do the job but a global consideration must

be made to optimize the total cost of the system according the

the requested specification.

When the Full Scale Pressure has to be sent with accuracy,

the calibration procedure may be executed in different ways.

For instance, the module may be calibrated directly using

Up/Down push buttons.

The gain of the chain is set by changing the VRH voltage of

the ratiometric A/D converter with the R/2R ladder network

circuit which is directly drived by the ports of the MCU. (See

Figure 12.)

Using a communication bus, the calibration procedure may

be executed from a host computer. In both cases, the setting

value is stored in the EEROM of the MCU.

The gain may be also set using a potentiometer in place of

the resistor Rf. But, this component is expensive, taking into

account that it must be stable over the temperature range at

long term.

MC68HC05B6

VRH

CH1

CH2

VDD

VRL

VSS

R/2R

LADDER

NETWORK

I/O

+ 5 V

0 V

DOWN

+ 5 V

Figure 12.

BUS

Table 1. Pressure Conversion Table

Unity

mbar

Torr

atm

at=kp/cm2

mWS

psi

1 N/m2 = 1 Pascal

0.01

7.5 10–3

—

1 mbar

100

0.75

—

0.0102

0.014

1 Torr = 1 mmHg

133.32

1.333

—

0.019

1 atm (1)

101325

1013.2

760

1.033

10.33

14.69

1 at = 1 kp/cm2 (2)

98066.5

981

735.6

0.97

14.22

1 m of water

9806.65

98.1

73.56

0.097

0.1

1.422

1 lb/sqin = 1 psi

6894.8

68.95

51.71

0.068

—

(1) Normal atmosphere

(2) Technical atmosphere

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

MPXM2102AS датащи(PDF) 353 Page - Motorola, Inc

MPXM2102AS датащи(HTML) 353 Page - Motorola, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL