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參數(shù)資料
| 型號： | MAX6678AEP92+ |
| 廠商： | Maxim Integrated |
| 文件頁數(shù)： | 15/19頁 |
| 文件大?。?/td> | 669K |
| 描述： | IC TEMP MONITOR 2CH PWM 20-QSOP |
| 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)控器 |
| 傳感器類型： | 內(nèi)部和外部 |
| 精確度： | ±4°C（最小值） |
| 輸出類型： | 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： | -40°C ~ 125°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 20-SSOP（0.154"，3.90mm 寬） |
| 供應(yīng)商設(shè)備封裝： | 20-QSOP |
| 包裝： | 管件 |
GPIO Function Register (15h)
The GPIO function register (15h) sets the GPIO_ states.
Write a zero to set a GPIO as an output. Write a one to
set a GPIO as an input.
GPIO Value Register (16h)
The GPIO value register (16h) contains the state of
each GPIO input when a GPIO is configured as an
input. When configured as an output, write a one or
zero to set the value of the GPIO output.
Applications Information
Remote-Diode Considerations
Temperature accuracy depends upon having a good-
quality, diode-connected, small-signal transistor.
Accuracy has been experimentally verified for all the
devices listed in Table 7. The MAX6678 can also direct-
ly measure the die temperature of CPUs and other ICs
with on-board temperature-sensing diodes.
The transistor must be a small-signal type with a rela-
tively high forward voltage. This ensures that the input
voltage is within the A/D input voltage range. The for-
ward voltage must be greater than 0.25V at 10礎(chǔ) at the
highest expected temperature. The forward voltage
must be less than 0.95V at 100礎(chǔ) at the lowest expect-
ed temperature. The base resistance has to be less
than 100&. Tight specification of forward-current gain
(+50 to +150, for example) indicates that the manufac-
turer has good process control and that the devices
have consistent characteristics.
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 MAX6678 is 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
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
MAX6678 is 1.008.
As an example, assume the MAX6678 is configured
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 (358.15K), the mea-
sured temperature is +82.87癈 (356.02K), 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礎(chǔ) and
100礎(chǔ), change in the measured voltage is:
Since 1癈 corresponds to 198.6礦, 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.
For best accuracy, the discrete transistor should be a
small-signal device with its collector connected to GND
and base connected to DXN. Table 7 lists examples of
discrete transistors that are appropriate for use with the
MAX6678.
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ACTUAL
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1
2-Channel Temperature Monitor with Dual Automatic
PWM Fan-Speed Controller and Five GPIOs
______________________________________________________________________________________ 15
Pentium is a registered trademark of Intel Corp.
Athlon is a trademark of AMD.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX6678AEP92+ | 功能描述:板上安裝溫度傳感器 2Ch Temperature Monitor 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 |
| MAX6678AEP92+T | 功能描述:板上安裝溫度傳感器 2Ch Temperature Monitor 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 |
| MAX6678AEP92-T | 功能描述:板上安裝溫度傳感器 2Ch Temperature Monitor 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 |
| MAX6678AEP94 | 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(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 |
| MAX6678AEP94+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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