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参数资料
| 型号： | MAX6646MUA+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 12/16页 |
| 文件大小： | 194K |
| 描述： | IC SENSOR REMOTE SMBUS 8UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| 功能： | 温度监控系统（传感器） |
| 传感器类型： | 内部和外部 |
| 感应温度： | -55°C ~ 125°C，外部传感器 |
| 精确度： | ±3°C 本地（最大），±3.2°C 远程（最大） |
| 拓扑： | ADC，多路复用器，寄存器库 |
| 输出类型： | I²C?/SMBus? |
| 输出警报： | 是 |
| 输出风扇： | 是 |
| 电源电压： | 3 V ~ 5.5 V |
| 工作温度： | -55°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 8-uMAX |
| 包装： | 管件 |
| 产品目录页面： | 1425 (CN2011-ZH PDF) |
+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
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T
T
n
n
T
ACTUAL
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NOMINAL
M
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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).
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6646MUA+ | 功能描述:板上安装温度传感器 145C SMBus-Comp Remote/Local Sensor RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
| MAX6646MUA+T | 功能描述:板上安装温度传感器 145C SMBus-Comp Remote/Local Sensor RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
| MAX6646MUA-T | 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
| MAX6646YMUA+ | 功能描述:板上安装温度传感器 145C SMBus-Comp Remote/Local Sensor RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
| MAX6646YMUA+T | 功能描述:板上安装温度传感器 145C SMBus-Comp Remote/Local Sensor RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor |
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