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| 型号： | MAX6642ATT90+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 10/14页 |
| 文件大小： | 154K |
| 描述： | IC TEMP SENSOR SMBUS 6-TDFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 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： | -40°C ~ 125°C，0°C ~ 150°C |
| 精确度： | ±3°C（最小值） |
| 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： | 无 |
| 电源电压： | 3 V ~ 5.5 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 6-WDFN 裸露焊盘 |
| 供应商设备封装： | 6-TDFN 裸露焊盘（3x3） |
| 包装： | 标准包装 |
| 产品目录页面： | 1425 (CN2011-ZH PDF) |
| 其它名称： | MAX6642ATT90+TDKR |
III. A thermal diode on the substrate of an IC is normally
a PNP with its collector grounded. Connect the anode
(emitter) to DXP and the cathode to GND of the
MAX6642.
If a sense transistor with an ideality factor other than
1.008 is used, the output data is different from the data
obtained with the optimum ideality factor. 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 and
n
NOMIMAL
for the MAX6642 is 1.008.
As an example, assume you want to use the MAX6642
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 +82.91癈 (356.02K), 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 and
100礎, the change in the measured voltage due to
series resistance is:
擵
M
= R
S
(100礎 - 10礎) = 90礎 R
S
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.
Discrete Remote Diodes
When the remote-sensing diode is a discrete transistor,
connect its collector and base together. Table 7 lists
examples of discrete transistors that are appropriate for
use with the MAX6642.
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 10礎, and at the lowest expected tempera-
ture, the forward voltage must be less than 0.95V at
100礎. Large power transistors must not be used. Also,
ensure that the base resistance is less than 100? Tight
specifications for forward current gain (50 < ?<150, for
example) indicate that the manufacturer has good
process controls and that the devices have consistent
V
BE
characteristics.
Manufacturers of discrete transistors do not normally
specify or guarantee ideality factor. This is normally not
a problem since good-quality discrete transistors tend
to have ideality factors that fall within a relatively narrow
3 0 453
1 36
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= +
?/DIV>
.
.
C
C
90
198 6
0 453
?/DIV>
?/DIV>
?/DIV>
?/DIV>
=
?/DIV>
?/DIV>
V
V
C
C
.
.
T
T
n
n
T
T
ACTUAL
M
NOMINAL
M
M
=
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
=
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
=
1
1 008
1 002
1 00599
.
.
( .
)
T T
n
n
M ACTUAL
NOMINAL
=
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
1
?癈, SMBus-Compatible Remote/Local
Temperature Sensor with Overtemperature Alarm
10 ______________________________________________________________________________________
MANUFACTURER
MODEL NO.
Central Semiconductor (USA)
CMPT3906
Rohm Semiconductor (USA)
SST3906
Samsung (Korea)
KST3906-TF
Siemens (Germany)
SMBT3906
Zetex (England)
FMMT3906CT-ND
Table 7. Remote-Sensor Transistor
Manufacturers
Note: Discrete transistors must be diode connected (base short-
ed to collector).
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6642ATT92 | 制造商:Maxim Integrated Products 功能描述:- Rail/Tube |
| MAX6642ATT92+ | 制造商:Maxim Integrated Products 功能描述:TEMP SENSOR DGTL 2-WIRE 6TDFN EP - Rail/Tube |
| MAX6642ATT92+T | 功能描述:板上安装温度传感器 SMBus-Compatible Temperature 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 |
| MAX6642ATT92-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 |
| MAX6642ATT94+ | 制造商:Maxim Integrated Products 功能描述:TEMP SENSOR DGTL 2-WIRE 6TDFN EP - Rail/Tube |
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