V2 - V1

T2 - T1

u

¹

·

V - V1 =

(T - T1)

30

)

00433

.

0

(

2

mV

V

8

.

2230

00433

.

0

4

582

.

13

582

.

13

T

TEMP

2

u

u

u

ª

º

ª

º

«

»

«

»

¬

¼ ¬

¼

2

TEMP

2

mV

mV

V

mV = 2230.8mV - 13.582

T - 30°C

- 0.00433

T - 30°C

°C

°C

10

LMT87

SNIS170E – JANUARY 2014 – REVISED OCTOBER 2017

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Product Folder Links: LMT87

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Copyright © 2014–2017, Texas Instruments Incorporated

Feature Description (continued)

Table 3. LMT87 Transfer Table (continued)

TEMP

(°C)

VOUT

(mV)

TEMP

(°C)

VOUT

(mV)

TEMP

(°C)

VOUT

(mV)

TEMP

(°C)

VOUT

(mV)

TEMP

(°C)

VOUT

(mV)

–37

3121

3

2593

43

2054

83

1497

123

929

–36

3108

4

2580

44

2040

84

1483

124

915

–35

3095

5

2567

45

2026

85

1469

125

901

–34

3082

6

2553

46

2012

86

1455

126

886

–33

3069

7

2540

47

1999

87

1441

127

872

–32

3056

8

2527

48

1985

88

1427

128

858

–31

3043

9

2513

49

1971

89

1413

129

843

–30

3030

10

2500

50

1958

90

1399

130

829

–29

3017

11

2486

51

1944

91

1385

131

814

–28

3004

12

2473

52

1930

92

1371

132

800

–27

2991

13

2459

53

1916

93

1356

133

786

–26

2978

14

2446

54

1902

94

1342

134

771

–25

2965

15

2433

55

1888

95

1328

135

757

–24

2952

16

2419

56

1875

96

1314

136

742

–23

2938

17

2406

57

1861

97

1300

137

728

–22

2925

18

2392

58

1847

98

1286

138

713

–21

2912

19

2379

59

1833

99

1272

139

699

–20

2899

20

2365

60

1819

100

1257

140

684

–19

2886

21

2352

61

1805

101

1243

141

670

–18

2873

22

2338

62

1791

102

1229

142

655

–17

2859

23

2325

63

1777

103

1215

143

640

–16

2846

24

2311

64

1763

104

1201

144

626

–15

2833

25

2298

65

1749

105

1186

145

611

–14

2820

26

2285

66

1735

106

1172

146

597

–13

2807

27

2271

67

1721

107

1158

147

582

–12

2793

28

2258

68

1707

108

1144

148

568

–11

2780

29

2244

69

1693

109

1130

149

553

150

538

Although the LMT87 is very linear, the response does have a slight umbrella parabolic shape. This shape is very

accurately reflected in Table 3. The transfer table can be calculated by using the parabolic equation (Equation 1).

(1)

The parabolic equation is an approximation of the transfer table and the accuracy of the equation degrades

slightly at the temperature range extremes. Equation 1 can be solved for T resulting in:

(2)

For an even less accurate linear transfer function approximation, a line can easily be calculated over the desired

temperature range from Table 3 using the two-point equation (Equation 3):

where

•

V is in mV,

•

T is in °C,

•

T1 and V1 are the coordinates of the lowest temperature,

•

and T2 and V2 are the coordinates of the highest temperature.

(3)