EXAMPLE 1: Finding Worst-Case Accuracy From –15°C to +50°C

Accuracy

=Accuracy

+ T

Slope1

D ´

MAX ( 15°Cto 25°C)

(

-

25°C)

MAX

(2)

Accuracy

=0.3 C+( 15 C

25 C)

°

-

MAX ( 15°Cto 25°C)

-

° -

°

-7

=+0.58°C

m°C

°C

(3)

Accuracy

=Accuracy

+ T

Slope2

D ´

MAX (25°Cto 50°C)

(25°C)

MAX

(4)

Accuracy

=0.3 C+(50 C

25 C)

°

´

MAX (25°Cto 50°C)

° -

°

5

=+0.425°C

m°C

°C

(5)

Accuracy

=Accuracy

+ T

Slope1

D ´

MIN( 15°Cto 25°C)

(

-

25°C)

MIN

(6)

Accuracy

= 0.5 C+( 15 C

25 C)

-

°

-

MIN( 15°Cto 25°C)

-

° -

°

0

= 0.5

-

°C

m°C

°C

(7)

Accuracy

=Accuracy

+ T

Slope2

D ´

MIN(25°Cto 50°C)

(25°C)

MIN

(8)

Accuracy

= 0.5 C+(50 C

25 C)

-

°

MIN(25°Cto 50°C)

° -

°

0

= 0.5

-

°C

m°C

°C

(9)

EXAMPLE 2: Finding Worst-Case Accuracy From +25°C to +100°C

Accuracy

=Accuracy

+ T

Slope2

D ´

MAX (25°Cto 100°C)

(

MAX

+ T

Slope3

D ´

25°C)

MAX

(10)

Accuracy

=0.3 C+(85 C

25 C)

°

MAX (25°Cto 100°C)

° -

°

4.5

m°C

°C

+(100 C

85 C)

° -

°

8

=+0.690°C

m°C

°C

(11)

Accuracy

=Accuracy

+ T

Slope2

D ´

MIN(25°Cto 100°C)

(

MIN

+ T

Slope3

D ´

25°C)

MIN

(12)

Accuracy

= 0.5 C+(85 C

25 C)

-

°

-

MIN(25°Cto 100°C)

°

°

0

m°C

°C

+(100 C

85 C)

° -

°

0

= 0.5

-

°C

m°C

°C

(13)

TMP112

As an example, if the user is concerned only about the temperature accuracy between –15°C to +50°C, the

worst-case accuracy could be determined by using the two slope calculations of Equation 2 and Equation 4:

The same calculations must be applied to the minimum case:

Based on the above calculations, a user can expect a worst-case accuracy of +0.58°C to –0.5°C in the

temperature range of –15°C to +50°C.

If the desired temperature range falls in the region of slope 3, it is necessary to first calculate the worst-case

value from +25°C to +85°C and add it to the change in temperature multiplied by the span error of slope 3. As an

example, consider the temperature range of +25°C to +125°C as shown in Equation 10:

Performing the same calculation for the minimum case is shown in Equation 12:

Copyright © 2009, Texas Instruments Incorporated

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