12

Atmel AVR1923

8394B-AVR-02/12

5.7 Analog I/O

5.7.1 Temperature sensor

The temperature sensor circuitry consists of a serial connection of a normal and a

NTC resistor. The NTC sensor is from Murata and some part details are shown in

Table 5-7, more information can be obtained from the manufacturer’s website.

Table 5-7. NTC characteristics.

Global part number

NCP18WF104J03RB

Resistance (25

℃)

100kΩ ±5%

B-Constant (25/50

℃) (reference value)

4250K ±2%

B-Constant (25/80

℃) (reference value)

4303K

B-Constant (25/85

℃) (reference value)

4311K

B-Constant (25/100

℃) (reference value)

4334K

Table 5-8 shows the temperature vs. resistance characteristic. The values are

available from Murata in the datasheet of the NTC.

Table 5-8. Resistance vs. temperature (from Murata).

Temp.

[°C]

NTC

resistance

[kΩ]

Temp.

[°C]

NTC

resistance

[kΩ]

Temp.

[°C]

NTC

resistance

[kΩ]

Temp.

[°C]

NTC

resistance

[kΩ]

-30

2197.225

0

357.012

30

79.222

60

22.224

-29

2055.558

1

338.006

31

75.675

61

21.374

-28

1923.932

2

320.122

32

72.306

62

20.561

-27

1801.573

3

303.287

33

69.104

63

19.782

-26

1687.773

4

287.434

34

66.061

64

19.036

-25

1581.881

5

272.500

35

63.167

65

18.323

-24

1483.100

6

258.426

36

60.415

66

17.640

-23

1391.113

7

245.160

37

57.797

67

16.986

-22

1305.413

8

232.649

38

55.306

68

16.360

-21

1225.531

9

220.847

39

52.934

69

15.760

-20

1151.037

10

209.710

40

50.677

70

15.184

-19

1081.535

11

199.196

41

48.528

71

14.631

-18

1016.661

12

189.268

42

46.482

72

14.101

-17

956.080

13

179.890

43

44.533

73

13.592

-16

899.481

14

171.028

44

42.675

74

13.104

-15

846.579

15

162.651

45

40.904

75

12.635

-14

797.111

16

154.726

46

39.213

76

12.187

-13

750.834

17

147.232

47

37.601

77

11.757

-12

707.524

18

140.142

48

36.063

78

11.344

-11

666.972

19

133.432

49

34.595

79

10.947

-10

628.988

20

127.080

50

33.195

80

10.566

-9

593.342

21

121.066

51

31.859

81

10.200

-8

559.931

22

115.368

52

30.584

82

9.848