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參數(shù)資料
| 型號： | MAX6678AEP92+ |
| 廠商： | Maxim Integrated |
| 文件頁數(shù)： | 16/19頁 |
| 文件大?。?/td> | 669K |
| 描述： | IC TEMP MONITOR 2CH PWM 20-QSOP |
| 產(chǎn)品培訓模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標準包裝： | 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） |
| 供應商設備封裝： | 20-QSOP |
| 包裝： | 管件 |
ADC Noise Filtering
The integrating ADC has inherently good noise rejec-
tion, especially of low-frequency signals such as
60Hz/120Hz power-supply hum. Micropower operation
places constraints on high-frequency noise rejection.
Lay out the PC board carefully with proper external
noise filtering for high-accuracy remote measurements
in electrically noisy environments.
Filter high-frequency electromagnetic interference
(EMI) at DXP and DXN with an external 2200pF capaci-
tor connected between the two inputs. This capacitor
can be increased to about 3300pF (max), including
cable capacitance. A capacitance higher than 3300pF
introduces errors due to the rise time of the switched-
current source.
Twisted Pairs and Shielded Cables
For remote-sensor distances longer than 8in, or in partic-
ularly noisy environments, a twisted pair is recommend-
ed. Its practical length is 6ft to 12ft (typ) before noise
becomes a problem, as tested in a noisy electronics labo-
ratory. For longer distances, the best solution is a shield-
ed twisted pair like that used for audio microphones. For
example, Belden 8451 works well for distances up to
100ft in a noisy environment. Connect the twisted pair to
DXP and DXN and the shield to ground, and leave the
shields remote end unterminated. Excess capacitance at
DXN or DXP limits practical remote-sensor distances (see
the Typical Operating Characteristics).
For very long cable runs, the cables parasitic capaci-
tance often provides noise filtering, so the recommend-
ed 2200pF capacitor can often be removed or reduced
in value. Cable resistance also affects remote-sensor
accuracy. A 1& series resistance introduces about
+1/2癈 error.
PC Board Layout Checklist
1) Place the MAX6678 as close as practical to the
remote diode. In a noisy environment, such as a
computer motherboard, this distance can be 4in to
8in, or more, as long as the worst noise sources
(such as CRTs, clock generators, memory buses,
and ISA/PCI buses) are avoided.
2) Do not route the DXP/DXN lines next to the deflection
coils of a CRT. Also, do not route the traces across a
fast memory bus, which can easily introduce +30癈
error, even with good filtering. Otherwise, most noise
sources are fairly benign.
3) Route the DXP and DXN traces parallel and close to
each other, away from any high-voltage traces such
as +12VDC. Avoid leakage currents from PC board
contamination. A 20M& leakage path from DXP
ground causes approximately +1癈 error.
4) Connect guard traces to GND on either side of the
DXP/DXN traces. With guard traces, placing routing
near high-voltage traces is no longer an issue.
5) Route as few vias and crossunders as possible to
minimize copper/solder thermocouple effects.
6) When introducing a thermocouple, make sure that
both the DXP and the DXN paths have matching
thermocouples. In general, PC board-induced ther-
mocouples are not a serious problem. A copper sol-
der thermocouple exhibits 3礦/癈, and it takes
approximately 200礦 of voltage error at DXP/DXN to
cause a +1癈 measurement error, so most parasitic
thermocouple errors are swamped out.
7) Use wide traces. Narrow traces are more inductive
and tend to pick up radiated noise. The 10-mil widths
and spacings recommended are not absolutely nec-
essary (as they offer only a minor improvement in
leakage and noise), but use them where practical.
8) Placing an electrically clean copper ground plane
between the DXP/DXN traces and traces carrying
high-frequency noise signals helps reduce EMI.
2-Channel Temperature Monitor with Dual Automatic
PWM Fan-Speed Controller and Five GPIOs
16 ______________________________________________________________________________________
Table 7. Remote-Sensor Transistor
Manufacturers
MANUFACTURER
MODEL NO.
Central Semiconductor (USA)
CMPT3906
Rohm Semiconductor (USA)
SST3906
Samsung (Korea)
KST3906-TF
Siemens (Germany)
SMBT3906
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相關代理商/技術參數(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 關閉: 安裝風格: 封裝 / 箱體: 設備功能: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 關閉: 安裝風格: 封裝 / 箱體: 設備功能: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 關閉: 安裝風格: 封裝 / 箱體: 設備功能: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 關閉: 安裝風格: 封裝 / 箱體: 設備功能: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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