Thermal Diodes

OUT

GND

LMT87, LMT87-Q1

www.ti.com

SNIS170C – JAN 2014 – REVISED OCTOBER 2015

8 Detailed Description

8.1 Overview

The LMT87 and LMT87-Q1 are analog output temperature sensors. The temperature sensing element is

comprised of a simple base emitter junction that is forward biased by a current source. The temperature sensing

element is then buffered by an amplifier and provided to the OUT pin. The amplifier has a simple push-pull output

stage thus providing a low impedance output source.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 LMT87/LMT87-Q1 Transfer Function

The output voltage of the LMT87 and LMT87-Q1, across the complete operating temperature range is shown in

Table 1. This table is the reference from which the LMT87 and LMT87-Q1 accuracy specifications (listed in the

Accuracy Characteristics section) are determined. This table can be used, for example, in a host processor look-

up table. A file containing this data is available for download at LMT87 product folder under Tools and Software

Models.

Table 1. LMT87/LMT87-Q1 Transfer Table

TEMP

TEMP

TEMP

TEMP

TEMP

(°C)

(mV)

(°C)

(mV)

(°C)

(mV)

(°C)

(mV)

(°C)

(mV)

-50

3277

-10

2767

30

2231

70

1679

110

1115

-49

3266

-9

2754

31

2217

71

1665

111

1101

-48

3254

-8

2740

32

2204

72

1651

112

1087

-47

3243

-7

2727

33

2190

73

1637

113

1073

-46

3232

-6

2714

34

2176

74

1623

114

1058

-45

3221

-5

2700

35

2163

75

1609

115

1044

-44

3210

-4

2687

36

2149

76

1595

116

1030

-43

3199

-3

2674

37

2136

77

1581

117

1015

-42

3186

-2

2660

38

2122

78

1567

118

1001

-41

3173

-1

2647

39

2108

79

1553

119

987

-40

3160

0

2633

40

2095

80

1539

120

973

-39

3147

1

2620

41

2081

81

1525

121

958

-38

3134

2

2607

42

2067

82

1511

122

944

-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

Copyright © 2014–2015, Texas Instruments Incorporated

Submit Documentation Feedback

9

Product Folder Links: LMT87 LMT87-Q1