User manual

Atmel AVR1925: XMEGA-C3 Xplained Hardware User’s Guide [APPLICATION NOTE]
42053A−AVR−02/2013
10
Table 4-7. 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
-7 528.602 23 109.970 53 29.366 83 9.510
-6 499.212 24 104.852 54 28.203 84 9.185
-5 471.632 25 100.000 55 27.091 85 8.873
-4 445.772 26 95.398 56 26.028 86 8.572
-3 421.480 27 91.032 57 25.013 87 8.283
-2 398.652 28 86.889 58 24.042 88 8.006
-1 377.193 29 82.956 59 23.113 89 7.738
Two common approximations can be used to model the temperature vs. resistance characteristic; these are the B
parameter and the Steinhart-Hart equations. Coefficients for both formulas can be calculated from Table 4-7.
When the inte
rnal reference VCC/1.6 is used and the ADC is measuring in signed single ended mode the codes
in Table 4-8 can be read from the ADC at
the various temperatures. The calculation is based on Table 4-7.
Table 4-8. ADC codes vs. temperature (signed single ended mode with internal VCC/1.6 reference).
ADC input [V] Temp. [°C] ADC codes ADC input [V] Temp. [°C] ADC codes
2.076 -14 2047 0.347 38 345
2.030 -13 2014 0.334 39 332
1.983 -12 1968 0.321 40 319
1.936 -11 1921 0.309 41 307
1.889 -10 1875 0.297 42 295
1.841 -9 1828 0.286 43 283