Thermal Diodes

OUT

GND

9

LMT87, LMT87-Q1

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SNIS170D – JANUARY 2014 – REVISED JUNE 2017

Product Folder Links: LMT87 LMT87-Q1

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Copyright © 2014–2017, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

The LMT87 and LMT87-Q1 are analog output temperature sensors. The electrical characteristics of the LMT87

and LMT87-Q1 are identical, so for clarity, the devices will be subsequently referred to as simply LMT87. 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

Full-Range Celsius Temperature Sensor (

−50°C to +150°C)

8.3 Feature Description

8.3.1 LMT87 Transfer Function

The output voltage of the LMT87, across the complete operating temperature range, is shown in Table 3. This

table is the reference from which the LMT87 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 the LMT87 product folder under Tools and Software Models.

Table 3. LMT87 Transfer Table

TEMP

(°C)

(mV)

TEMP

(°C)

(mV)

TEMP

(°C)

(mV)

TEMP

(°C)

(mV)

TEMP

(°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