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参数资料
| 型号： | MAX6648MUA+ |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | 温度/湿度传感器 |
| 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, SQUARE, SURFACE MOUNT |
| 封装： | LEAD FREE, MO-187CAA, USOP-8 |
| 文件页数： | 5/19页 |
| 文件大小： | 295K |
| 代理商： | MAX6648MUA+ |
surements. The noise can be reduced with careful PC
board layout and proper external noise filtering.
High-frequency EMI is best filtered at DXP and DXN
with an external 2200pF capacitor. Larger capacitor
values can be used for added filtering, but do not
exceed 3300pF because larger values can introduce
errors due to the rise time of the switched current
source.
PC Board Layout
Follow these guidelines to reduce the measurement
error of the temperature sensors:
1) Place the MAX6648/MAX6692 as close as is practi-
cal to the remote diode. In noisy environments, such
as a computer motherboard, this distance can be
4in to 8in (typ). This length can be increased if the
worst noise sources are avoided. Noise sources
include CRTs, clock generators, memory buses, and
ISA/PCI buses.
2) Do not route the DXP-DXN lines next to the deflec-
tion coils of a CRT. Also, do not route the traces
across fast digital signals, which can easily intro-
duce 30°C error, even with good filtering.
3) Route the DXP and DXN traces in parallel and in
close proximity to each other, away from any higher
voltage traces, such as 12VDC. Leakage currents
from PC board contamination must be dealt with
carefully since a 20M
leakage path from DXP to
ground causes about 1°C error. If high-voltage traces
are unavoidable, connect guard traces to GND on
either side of the DXP-DXN traces (Figure 4).
4) Route through as few vias and crossunders as pos-
sible to minimize copper/solder thermocouple
effects.
5) When introducing a thermocouple, make sure that
both the DXP and the DXN paths have matching
thermocouples. A copper-solder thermocouple
exhibits 3V/°C, and takes about 200V of voltage
error at DXP-DXN to cause a 1°C measurement
error. Adding a few thermocouples causes a negligi-
ble error.
6) Use wide traces. Narrow traces are more inductive
and tend to pick up radiated noise. The 10mil widths
and spacing recommended in Figure 4 are not
absolutely necessary, as they offer only a minor
improvement in leakage and noise over narrow
traces. Use wider traces when practical.
7) Add a 200
resistor in series with VCC for best noise
filtering (see Typical Operating Circuit).
8) Copper cannot be used as an EMI shield; only fer-
rous materials such as steel work well. Placing a
copper ground plane between the DXP-DXN traces
and traces carrying high-frequency noise signals
does not help reduce EMI.
Twisted-Pair and Shielded Cables
Use a twisted-pair cable to connect the remote sensor
for remote-sensor distance longer than 8in, or in very
noisy environments. Twisted-pair cable lengths can be
between 6ft and 12ft before noise introduces excessive
errors. For longer distances, the best solution is a
shielded twisted pair like that used for audio micro-
phones. For example, Belden 8451 works well for dis-
tances up to 100ft in a noisy environment. At the
device, connect the twisted pair to DXP and DXN and
the shield to GND. Leave the shield unconnected at the
remote sensor.
For very long cable runs, the cable’s parasitic capaci-
tance often provides noise filtering, so the 2200pF
capacitor can often be removed or reduced in value.
Cable resistance also affects remote-sensor accuracy.
For every 1
of series resistance, the error is approxi-
mately 0.5°C.
Thermal Mass and Self-Heating
When sensing local temperature, these devices are
intended to measure the temperature of the PC board to
which they are soldered. The leads provide a good ther-
mal path between the PC board traces and the die.
Thermal conductivity between the die and the ambient
air is poor by comparison, making air temperature mea-
surements impractical. Because the thermal mass of the
PC board is far greater than that of the MAX6648/
MAX6692, the devices follow temperature changes on
the PC board with little or no perceivable delay.
When measuring the temperature of a CPU or other IC
with an on-chip sense junction, thermal mass has virtu-
ally no effect; the measured temperature of the junction
tracks the actual temperature within a conversion cycle.
MAX6648/MAX6692
Precision SMBus-Compatible Remote/Local
Temperature Sensors with Overtemperature Alarms
______________________________________________________________________________________
13
______________________________________________________________________________________
13
MINIMUM
10MILS
GND
DXN
DXP
GND
Figure 4. Recommended DXP-DXN PC Traces
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6648MUA+ | 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 |
| MAX6648MUA+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 |
| MAX6648MUA-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 |
| MAX6648YMUA+ | 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 |
| MAX6648YMUA+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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