ADT7318ARQZ 查看數據表（PDF） - Analog Devices
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ADT7318ARQZ
Analog Devices
ADT7318ARQZ Datasheet PDF : 44 Pages
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ADT7316/ADT7317/ADT7318
Negative Temperatures
Offset Register Code (dec) = (0 V Temp) + 128
where D7 of Offset Register Code is set to 1 for negative
temperatures.
Example:
Offset Register Code (dec) = (−40) + 128 = 88d = 0x58
Because a negative temperature is input into the equation, DB7
(MSB) of the Offset Register Code is set to 1. Therefore, 0x58
becomes 0xD8:
0x58 + DB7 (1) = 0xD8
Positive Temperatures
Offset Register Code (dec) = 0 V Temp
Example:
Offset Register Code (dec) = 10d =0x0A
The following equation is used to work out the various
temperatures for the corresponding 8-bit DAC output:
8-Bit Temp = (DAC O/P ÷ 1 LSB) + (0 V Temp)
For example, if the output is 1.5 V, VREF-AB = 2.25 V, 8-bit DAC
has an LSB size = 2.25 V/256 = 8.79 × 10–3, and 0 V temp is at
−128°C, then the resultant temperature is
( ) 1.5 ÷ 8.79 × 10 −3 +(−128) = + 43o C
The following equation is used to work out the various
temperatures for the corresponding 10-bit DAC output
10-Bit Temp = ((DAC O/P ÷ 1 LSB) × 0.25) + (0 V Temp)
For example, if the output is 0.4991 V, VREF-AB = 2.25 V, 10-bit
DAC has an LSB size = 2.25 V/1024 = 2.197 × 10-3, and 0 V temp
is at −40°C, then the resulting temperature is
(( ) ) 0.4991 ÷ 2.197 × 10−3 × 0.25 + (− 40) = 16.75o C
Table 6. Thermal Voltage Output (0 V to VREF-AB)
Output Voltage (V) Default (°C) Max (°C) Sample (°C)
0
−40
−128
0
0.5
+17
−71
+56
1
+73
−15
+113
1.12
+87
−1
+127
1.47
+127
+39
UDB1
1.5
UDB1
+42
UDB1
2
UDB1
+99
UDB1
2.25
UDB1
+127
UDB1
1Upper dead band has been reached. DAC output is not capable of increasing
(see Figure 3).
Table 7. Thermal Voltage Output (0 V to 2 VREF-AB)
Output Voltage (V) Default (°C) Max (°C) Sample (°C)
0
−40
−128
0
0.25
−26
−114
+14
0.5
+12
−100
+28
0.75
+3
−85
+43
1
+17
−71
+57
1.12
+23
−65
+63
1.47
+43
−45
+83
1.5
+45
−43
+85
2
+73
−15
+113
2.25
+88
0
+127
2.5
+102
+14
UDB1
2.75
+116
+28
UDB1
3
UDB1
+42
UDB1
3.25
UDB1
+56
UDB1
3.5
UDB1
+70
UDB1
3.75
UDB1
+85
UDB1
4
UDB1
+99
UDB1
4.25
UDB1
+113
UDB1
4.5
UDB1
+127
UDB1
1Upper dead band has been reached. DAC output is not capable of increasing
(see Figure 3).
Figure 43 shows the DAC output vs. temperature for a
VREF-AB = 2.25 V.
2.25
2.10
1.95
1.80
0V = –128°C
1.65
1.50
1.35
0V = –40°C
1.20
1.05
0.90
0.75
0.60
0V = 0°C
0.45
0.30
0.15
0
–128 –110 –90 –70 –50 –30 –10 10 30 50 70 90 110 127
TEMPERATURE (°C)
Figure 43. 10-Bit DAC Output vs. Temperature, VREF-AB = 2.25 V
Rev. B | Page 22 of 44
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