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參數(shù)資料
| 型號： | MAX6691 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類： | 熱敏電阻 |
| 英文描述： | Four-Channel Thermistor Temperature-to-Pulse- Width Converter |
| 中文描述： | 四通道、熱敏電阻溫度至脈寬轉(zhuǎn)換器 |
| 文件頁數(shù)： | 5/7頁 |
| 文件大?。?/td> | 151K |
| 代理商： | MAX6691 |
The relationship between temperature and resistance
of an NTC thermistor is highly nonlinear. However, by
connecting the thermistors in series with a properly
chosen resistor (R
EXT
) and using the MAX6691 to mea-
sure the voltage across the resistor, a reasonably linear
transfer function can be obtained over a limited temper-
ature range. Linearity improves for smaller temperature
ranges.
Figures 3 and 4 show typical T
HIGH
/T
LOW
curves for a
standard thermistor in conjunction with values of R
EXT
chosen to optimize linearity over two series resistors
chosen to optimize linearity over two different tempera-
ture ranges.
NTC thermistors are often described by the resistance
at +25
°
C. Therefore, a 10k
thermistor has a resis-
tance of 10k
at +25
°
C. When choosing a thermistor,
ensure that the thermistor
’
s minimum resistance (which
occurs at the maximum expected operating tempera-
ture) in series with R
EXT
does not cause the voltage ref-
erence output current to exceed about 1mA. Some
standard 10k
thermistors with similar characteristics
are listed in Table 1.
Choosing R
EXT
Choose R
EXT
to minimize nonlinearity errors from the
thermistor:
1) Decide on the temperature range of interest (for
example 0
°
C to +70
°
C).
2) Find the thermistor values at the limits of the tem-
perature range. R
MIN
is the minimum thermistor
value (at the maximum temperature) and R
MAX
is
the maximum thermistor value (at the minimum tem-
perature). Also find R
MID
, the thermistor resistance
in the middle of the temperature range (+35
°
C for
the 0
°
C to +70
°
C range).
3) Find R
EXT
using the equation below:
(
+
Power-Supply Considerations
The MAX6691 accuracy is relatively unaffected by
power-supply coupled noise. In most applications,
R
R
R
R
2
R
R
R
R
MIN
MAX
MIN
MAX
MIN
MAX
MID
EXT
MIN
= R
+
)
×
2
M
Four-Channel Thermistor Temperature-to-Pulse-
Width Converter
_______________________________________________________________________________________
5
Figure 2. Thermistor Resistance vs. Temperature
0
20
40
60
80
100
120
-40
0
-20
20
40
60
80
100
120
THERMISTOR RESISTANCE
vs. TEMPERATURE
TEMPERATURE (
°
C)
T
)
Figure 3. T
HIGH
/T
LOW
vs. Temperature, R
EXT
= 5110
T
HIGH
/T
LOW
vs. TEMPERATURE FOR BETATHERM
10K3A1 THERMISTOR WITH R
EXT
= 5110
1.2
TEMPERATURE (
°
C)
T
H
/
L
120
100
80
60
40
20
0.2
0.4
0.6
0.8
1.0
0
0
140
Figure 4. T
HIGH
/T
LOW
vs. Temperature, R
EXT
= 5110
T
HIGH
/T
LOW
vs. TEMPERATURE FOR BETATHERM
10K3A1 THERMISTOR WITH R
EXT
= 7680
1.0
TEMPERATURE (
°
C)
T
H
/
L
100
80
40
60
0
20
-20
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0
-40
120
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參數(shù)描述 |
|---|---|
| MAX6691MUB | 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC - 多種 RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 分辨率:8 bit 工作電源電壓:2.7 V to 5.5 V 功耗: 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:MSOP-10 封裝:Reel |
| MAX6691MUB+ | 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC - 多種 4Ch Thermistor Temp to-Pulse-Width RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 分辨率:8 bit 工作電源電壓:2.7 V to 5.5 V 功耗: 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:MSOP-10 封裝:Reel |
| MAX6691MUB+T | 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC - 多種 4Ch Thermistor Temp to-Pulse-Width RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 分辨率:8 bit 工作電源電壓:2.7 V to 5.5 V 功耗: 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:MSOP-10 封裝:Reel |
| MAX6691MUB-T | 功能描述:數(shù)據(jù)轉(zhuǎn)換 IC - 多種 RoHS:否 制造商:Texas Instruments 轉(zhuǎn)換器數(shù)量:1 分辨率:8 bit 工作電源電壓:2.7 V to 5.5 V 功耗: 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:MSOP-10 封裝:Reel |
| MAX6692EVKIT | 功能描述:板上安裝溫度傳感器 Evaluation System/Evaluation Kit for the MAX6648 MAX6649 MAX6692 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
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