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參數(shù)資料
| 型號： | MAX6649MUA/V+ |
| 廠商： | Maxim Integrated |
| 文件頁數(shù)： | 12/16頁 |
| 文件大?。?/td> | 194K |
| 描述： | IC SENSOR REMOTE SMBUS 8UMAX |
| 產(chǎn)品培訓(xùn)模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標(biāo)準(zhǔn)包裝： | 50 |
| 功能： | 溫度監(jiān)控系統(tǒng)（傳感器） |
| 傳感器類型： | 內(nèi)部和外部 |
| 感應(yīng)溫度： | -55°C ~ 125°C，外部傳感器 |
| 精確度： | ±3°C 本地（最大），±3.2°C 遠(yuǎn)程（最大） |
| 拓?fù)洌?/td> | ADC，多路復(fù)用器，寄存器庫 |
| 輸出類型： | I²C?/SMBus? |
| 輸出警報： | 是 |
| 輸出風(fēng)扇： | 是 |
| 電源電壓： | 3 V ~ 5.5 V |
| 工作溫度： | -55°C ~ 125°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 8-TSSOP，8-MSOP（0.118"，3.00mm 寬） |
| 供應(yīng)商設(shè)備封裝： | 8-uMAX |
| 包裝： | 管件 |
+145癈 Precision SMBus-Compatible Remote/
Local Sensors with Overtemperature Alarms
12
Applications Information
Remote-Diode Selection
The MAX6646/MAX6647/MAX6649 can directly measure
the die temperature of CPUs and other ICs that have
on-board temperature-sensing diodes (see Typical
Operating Circuit), or they can measure the tempera-
ture of a discrete diode-connected transistor.
Effect of Ideality Factor
The accuracy of the remote temperature measurements
depends on the ideality factor (n) of the remote diode
(actually a transistor). The MAX6646/MAX6647/MAX6649
are optimized for n = 1.008, which is the typical value for
the Intel
?/DIV>
Pentium
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III and the AMD Athlon MP model 6.
If a sense transistor with a different ideality factor is used,
the output data is different. Fortunately, the difference is
predictable.
Assume a remote-diode sensor designed for a nominal
ideality factor n
NOMINAL
is used to measure the tem-
perature of a diode with a different ideality factor n
1
.
The measured temperature T
M
can be corrected using:
where temperature is measured in Kelvin.
As mentioned above, the nominal ideality factor of the
MAX6646/MAX6647/MAX6649 is 1.008. The following
example uses the MAX6646/MAX6647/MAX6649 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癈 (358.15 K), the mea-
sured temperature is +82.91癈 (356.02 K), which is an
error of -2.13癈.
Effect of Series Resistance
Series resistance in a sense diode contributes addition-
al errors. For nominal diode currents of 10糀 and
100糀, change in the measured voltage is:
Since 1癈 corresponds to 198.6糣, series resistance
contributes a temperature offset of:
Assume that the diode being measured has a series
resistance of 3? 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 3? the total offset can be cal-
culated by adding error due to series resistance with
error due to ideality factor:
1.36癈 - 2.13癈 = -0.77癈
for a diode temperature of +85癈.
In this example, the effect of the series resistance and
the ideality factor partially cancel each other.
Discrete Remote Diodes
When the remote-sensing diode is a discrete transistor,
short the collector to the base. Table 10 lists examples
of discrete transistors that are appropriate for use with
the MAX6646/MAX6647/MAX6649.
Avoid violating the A/D input voltage range by using a
small-signal transistor with a relatively high forward volt-
age. The forward voltage at the highest expected tem-
perature must be greater than 0.25V at 10糀, and the
forward voltage at the lowest expected temperature
must be less than 0.95V at 100糀. Do not use large
power transistors. Ensure that the base resistance is
less than 100? Tight specifications for forward current
gain (50 < ?< 150, for example) indicate that the man-
ufacturer has good process controls and that the
devices have consistent V
BE
characteristics.
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100
10
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T
T
n
n
T
ACTUAL
M
NOMINAL
M
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M
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1 00599
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T
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n
M
ACTUAL
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1
Intel and Pentium are registered trademarks of Intel Corp.
AMD and Athlon are trademarks of Advanced Micro Devices, Inc.
MANUFACTURER
MODEL NO.
Central Semiconductor (USA)
CMPT3904
Rohm Semiconductor (USA)
SST3904
Samsung (Korea)
KST3904-TF
Siemens (Germany)
SMBT3904
Zetex (England)
FMMT3904CT-ND
Table 10. Remote-Sensor Transistor
Manufactures
Note: Discrete transistors must be diode connected (base
shorted to collector).
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX6652AUB+T | IC TEMP SENS/MON 10-UMAX |
| MAX6659MEE+T | IC TEMP SENSOR SMBUS 16-QSOP |
| MAX6661AEE+T | IC REG FAN SPEED 16-QSOP |
| MAX6664AEE+T | IC TEMP MON FAN CNTRL 16-QSOP |
| MAX6665ASA45+ | IC FAN CNTRL/DRVR 8-SOIC |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX6649YMUA+ | 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(zhǔn)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 |
| MAX6649YMUA+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(zhǔn)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 |
| MAX664C/D | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| MAX664CJA | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| MAX664CPA | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
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