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參數(shù)資料
| 型號： | MAX6648YMUA+ |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 溫度/濕度傳感器 |
| 英文描述： | Precision SMBus-Compatible Remote/Local Temperature Sensors with Overtemperature Alarms |
| 中文描述： | DIGITAL TEMP SENSOR-SERIAL, 10BIT(s), 0.80Cel, RECTANGULAR, SURFACE MOUNT |
| 封裝： | MICRO MAX-8 |
| 文件頁數(shù)： | 4/16頁 |
| 文件大小： | 194K |
| 代理商： | MAX6648YMUA+ |
MAX6648/MAX6692
Precision SMBus-Compatible Remote/Local
Temperature Sensors with Overtemperature Alarms
12
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(actually a transistor). The MAX6648/MAX6692 (not the
MAX6648Y/MAX6692Y) are optimized for n = 1.008,
which is the typical value for the Intel Pentium III and
the AMD Athlon MP model 6. If a sense transistor with a
different ideality factor is used, the output data is differ-
ent. Fortunately, the difference is predictable.
Assume a remote-diode sensor designed for a nominal
ideality factor nNOMINAL is used to measure the tem-
perature of a diode with a different ideality factor n1.
The measured temperature TM can be corrected using:
where temperature is measured in Kelvin.
As mentioned above, the nominal ideality factor of the
MAX6648/MAX6692 is 1.008. As an example, assume
you want to use the MAX6648/MAX6692 with a CPU
that has an ideality factor of 1.002.
If the diode has no series resistance, the measured
data is related to the real temperature as follows:
For a real temperature of +85°C (358.15 K), the mea-
sured temperature is +82.91°C (356.02 K), which is an
error of -2.13°C.
Effect of Series Resistance
Series resistance in a sense diode contributes addition-
al errors. For nominal diode currents of 10A and
100A, change in the measured voltage is:
Since 1°C corresponds to 198.6V, series resistance
contributes a temperature offset of:
Assume that the diode being measured has a series
resistance of 3Ω. The series resistance contributes an
offset of:
The effects of the ideality factor and series resistance
are additive. If the diode has an ideality factor of 1.002
and series resistance of 3Ω, the total offset can be cal-
culated by adding error due to series resistance with
error due to ideality factor:
1.36°C - 2.13°C = -0.77°C
for a diode temperature of +85°C.
In this example, the effect of the series resistance and
the ideality factor partially cancel each other.
For best accuracy, the discrete transistor should be a
small-signal device with its collector and base connect-
ed together. Table 9 lists examples of discrete transis-
tors that are appropriate for use with the MAX6648/
MAX6692.
The transistor must be a small-signal type with a rela-
tively high forward voltage; otherwise, the A/D input
voltage range can be violated. The forward voltage at
the highest expected temperature must be greater than
0.25V at 10A, and at the lowest expected tempera-
ture, the forward voltage must be less than 0.95V at
100A. Large power transistors must not be used.
Also, ensure that the base resistance is less than 100Ω.
Tight specifications for forward current gain (50 <
<150, for example) indicate that the manufacturer has
good process controls and that the devices have con-
sistent VBE characteristics.
Operation with 45nm Substrate PNPs
Small transistor geometries and specialized processes
can affect temperature measurement accuracy.
Parasitic series resistance can be higher, which
increases the measured temperature value. Beta may
3
0 453
1 36
Ω
×
° =°
..
C
90
198 6
0 453
μ
°
=
°
V
C
Ω
.
ΔVR
A
A R
MS
S
=μ
μ =
μ ×
()
100
10
90
TT
n
TT
ACTUAL
M
NOMINAL
MM
=
=
=
.
(.
)
1
1 008
1 002
1 00599
TT
n
M
ACTUAL
NOMINAL
=
1
Intel and Pentium are registered trademarks of Intel Corp.
MANUFACTURER
MODEL NO.
Central Semiconductor (USA)
CMPT3904
Rohm Semiconductor (USA)
SST3904
Samsung (Korea)
KST3904-TF
Siemens (Germany)
SMBT3904
Table 9. Remote-Sensor Transistor
Manufacturers
Note: Transistors must be diode connected (base shorted to
collector).
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX6648YMUA+ | 功能描述:板上安裝溫度傳感器 145C SMBus-Comp Remote/Local Sensor 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: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| MAX6648YMUA+T | 功能描述:板上安裝溫度傳感器 145C SMBus-Comp Remote/Local Sensor 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: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| MAX6649MUA | 功能描述:板上安裝溫度傳感器 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: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| MAX6649MUA/V+ | 功能描述:板上安裝溫度傳感器 145C SMBus-Comp Remote/Local Sensor 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: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| MAX6649MUA/V+T | 功能描述:板上安裝溫度傳感器 145C SMBus-Comp Remote/Local Sensor 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: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
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