Thermal Diodes

OUT

GND

LMT85, LMT85-Q1

www.ti.com

SNIS168C – MARCH 2013 – REVISED OCTOBER 2015

8 Detailed Description

8.1 Overview

The LMT85/LMT85-Q1 is an analog output temperature sensor. 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 LMT85/LMT85-Q1 Transfer Function

The output voltage of the LMT85/LMT85-Q1, across the complete operating temperature range, is shown in

Table 1. This table is the reference from which the LMT85/LMT85-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 LMT85 product folder under Tools and Software

Models.

Table 1. LMT85/LMT85-Q1 Transfer Table

TEMP

TEMP

TEMP

TEMP

TEMP

(°C)

(mV)

(°C)

(mV)

(°C)

(mV)

(°C)

(mV)

(°C)

(mV)

-50

1955

-10

1648

30

1324

70

991

110

651

-49

1949

-9

1639

31

1316

71

983

111

642

-48

1942

-8

1631

32

1308

72

974

112

634

-47

1935

-7

1623

33

1299

73

966

113

625

-46

1928

-6

1615

34

1291

74

957

114

617

-45

1921

-5

1607

35

1283

75

949

115

608

-44

1915

-4

1599

36

1275

76

941

116

599

-43

1908

-3

1591

37

1267

77

932

117

591

-42

1900

-2

1583

38

1258

78

924

118

582

-41

1892

-1

1575

39

1250

79

915

119

573

-40

1885

0

1567

40

1242

80

907

120

565

-39

1877

1

1559

41

1234

81

898

121

556

-38

1869

2

1551

42

1225

82

890

122

547

-37

1861

3

1543

43

1217

83

881

123

539

-36

1853

4

1535

44

1209

84

873

124

530

-35

1845

5

1527

45

1201

85

865

125

521

-34

1838

6

1519

46

1192

86

856

126

513

-33

1830

7

1511

47

1184

87

848

127

504

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