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參數(shù)資料
| 型號： | MAX1617MEE+T |
| 廠商： | Maxim Integrated |
| 文件頁數(shù)： | 8/20頁 |
| 文件大小： | 248K |
| 描述： | IC REMOTE/LOCAL TEMP SNSR 16QSOP |
| 產(chǎn)品培訓模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標準包裝： | 2,500 |
| 功能： | 溫度計，恒溫計 |
| 傳感器類型： | 內(nèi)部和外部 |
| 感應溫度： | -55°C ~ 125°C，外部傳感器 |
| 精確度： | ±3.5°C 本地（最大），±5°C 遠程（最大） |
| 拓撲： | ADC，比較器，多路復用器，寄存器庫 |
| 輸出類型： | I²C?/SMBus? |
| 輸出警報： | 是 |
| 輸出風扇： | 無 |
| 電源電壓： | 3 V ~ 5.5 V |
| 工作溫度： | -55°C ~ 125°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 16-SSOP（0.154"，3.90mm 寬） |
| 供應商設(shè)備封裝： | 16-QSOP |
| 包裝： | 帶卷 (TR) |
8
Remote/Local Temperature Sensor
with SMBus Serial Interface
MAX1617
Maxim Integrated
A/D Conversion Sequence
If a Start command is written (or generated automatical-
ly in the free-running auto-convert mode), both channels
are converted, and the results of both measurements
are available after the end of conversion. A BUSY status
bit in the status byte shows that the device is actually
performing a new conversion; however, even if the ADC
is busy, the results of the previous conversion are
always available.
Remote-Diode Selection
Temperature accuracy depends on having a good-qual-
ity, diode-connected small-signal transistor. See Table 1
for a recommended list of diode-connected small-signal
transistors. The MAX1617 can also directly measure the
die temperature of CPUs and other integrated circuits
having on-board temperature-sensing diodes.
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
must be greater than 0.25V at 10礎(chǔ); check to ensure
this is true at the highest expected temperature. The
forward voltage (V
DXP
- V
DXN
) must be less than 0.95V
at 100礎(chǔ); additionally, ensure the maximum V
DXP
(DXP
voltage) d (0.78 x V
CC
- 1.1) volts over your expected
range of temperature. Large power transistors dont
work at all. Also, ensure that the base resistance is less
than 100? Tight specifications for forward-current gain
(+50 to +150, for example) indicate that the manufac-
turer has good process controls and that the devices
have consistent VBE characteristics.
For heat-sink mounting, the 500-32BT02-000 thermal
sensor from Fenwal Electronics is a good choice. This
device consists of a diode-connected transistor, an
aluminum plate with screw hole, and twisted-pair cable
(Fenwal Inc., Milford, MA, 508-478-6000).
Thermal Mass and Self-Heating
Thermal mass can seriously degrade the MAX1617s
effective accuracy. The thermal time constant of the
QSOP-16 package is about 140sec in still air. For the
MAX1617 junction temperature to settle to within +1癈
after a sudden +100癈 change requires about five time
constants or 12 minutes. The use of smaller packages
for remote sensors, such as SOT23s, improves the situ-
ation. Take care to account for thermal gradients
between the heat source and the sensor, and ensure
that stray air currents across the sensor package do
not interfere with measurement accuracy.
Self-heating does not significantly affect measurement
accuracy. Remote-sensor self-heating due to the diode
current source is negligible. For the local diode, the
worst-case error occurs when auto-converting at the
fastest rate and simultaneously sinking maximum cur-
rent at the ALERT output. For example, at an 8Hz rate
and with ALERT sinking 1mA, the typical power dissi-
pation is V
CC
x 450礎(chǔ) plus 0.4V x 1mA. Package theta
J-A is about 150癈/W, so with V
CC
= 5V and no copper
PCB heat-sinking, the resulting temperature rise is:
dT = 2.7mW x 150癈/W = 0.4癈
Even with these contrived circumstances, it is difficult
to introduce significant self-heating errors.
ADC Noise Filtering
The ADC is an integrating type with inherently good
noise rejection, especially of low-frequency signals such
as 60Hz/120Hz power-supply hum. Micropower opera-
tion places constraints on high-frequency noise rejec-
tion; therefore, careful PCB layout and proper external
noise filtering are required for high-accuracy remote
measurements in electrically noisy environments.
High-frequency EMI is best filtered at DXP and DXN
with an external 2200pF capacitor. This value can be
increased to about 3300pF (max), including cable
capacitance. Higher capacitance than 3300pF intro-
duces errors due to the rise time of the switched cur-
rent source.
Nearly all noise sources tested cause the ADC measure-
ments to be higher than the actual temperature, typically
by +1癈 to +10癈, depending on the frequency and
amplitude (see Typical Operating Characteristics).
CMPT3904
Central Semiconductor (USA)
MMBT3904
Motorola (USA)
MMBT3904
SST3904
Rohm Semiconductor (Japan)
KST3904-TF
Samsung (Korea)
FMMT3904CT-ND
Zetex (England)
MANUFACTURER
MODEL NUMBER
SMBT3904
Siemens (Germany)
Table 1. Remote-Sensor Transistor
Manufacturers
Note: Transistors must be diode-connected (base shorted to
collector).
National Semiconductor (USA)
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1617MEE-TG075 | 制造商:Maxim Integrated Products 功能描述: |
| MAX1618EVKIT | 制造商:Maxim Integrated Products 功能描述:REMOTE TEMPERATURE SENSOR WITH SMBUS SERIAL I - Bulk |
| MAX1618MUB | 功能描述:板上安裝溫度傳感器 Sensors, Transducers 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(guān)閉: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| MAX1618MUB+ | 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(guān)閉: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| MAX1618MUB+T | 功能描述:板上安裝溫度傳感器 Sensors, Transducers 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(guān)閉: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
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