DA5536_009.doc

00005536589 ECN925

May 03, 2007

8

C3/II (8-Bit)

C5/II(8-Bit)

Word 1

DB7

DB6

DB5

DB4

DB3

DB2

DB1

DB0

DB7

DB6

DB5

DB4

DB3

DB2

DB1

DB0

C4/II (8-Bit)

C6(8-Bit)

Word 2

DB7

DB6

DB5

DB4

DB3

DB2

DB1

DB0

DB7

DB6

DB5

DB4

DB3

DB2

DB1

DB0

C5/I (4-Bit)

C1/II (12-Bit)

Word 3

DB11

DB10

DB9

DB8

DB11

DB10

DB9

DB8

DB7

DB6

DB5

DB4

DB3

DB2

DB1

DB0

C1/I

C4/I

C3/I

C2 (13-Bit)

Word 4

DB12

DB8

DB8

DB12

DB11

DB10

DB9

DB8

DB7

DB6

DB5

DB4

DB3

DB2

DB1

DB0

Fig. 4: Arrangement (Bit-pattern) of calibration data in Word1 to Word4.

SECOND-ORDER TEMPERATURE COMPENSATION

In order to obtain full accuracy over the whole temperature range, it is recommended to compensate for the

non-linearity of the output of the temperature sensor. This can be achieved by the second-order temperature

calculation, i.e. by replacing the block ‘Calculate actual temperature’ in flow chart Fig. 3 by the following

sequence:

Calculate actual temperature

Difference between the actual temperature and

reference temperature:

dT = (D2 - UT1) - ((D2-UT1)*(D2-UT1))/2

18

Actual temperature in °C

TEMP = 2000 + dT*(C6+262)/2

Calculate actual temperature

Difference between the actual temperature and

reference temperature:

dT = (D2 - UT1) - (9*(D2-UT1)*(D2-UT1))/2

18

Actual temperature in °C

TEMP = 2000 + dT*(C6+262)/2

D2≥UT1?

no

yes

Fig. 5: Flow chart for calculating the temperature to the optimum accuracy. The value for

dT thus obtained is

then used for the calculation of the temperature compensated pressure as shown in Fig. 3.