User manual

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 info
rmation 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