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參數(shù)資料
| 型號： | LM75A |
| 廠商： | NXP Semiconductors N.V. |
| 元件分類： | 溫度/濕度傳感器 |
| 英文描述： | Digital temperature sensor and thermal Watchdog |
| 中文描述： | 數(shù)字溫度傳感器和熱看門狗 |
| 文件頁數(shù)： | 7/18頁 |
| 文件大?。?/td> | 126K |
| 代理商： | LM75A |
Philips Semiconductors
Product data sheet
LM75A
Digital temperature sensor and thermal Watchdog
2004 Oct 05
7
FUNCTIONAL DESCRIPTION
General operation
The LM75A uses the on-chip band-gap sensor to measure the
device temperature with the resolution of 0.125
°
C and stores the
11-bit 2’s complement digital data, resulted from 11-bit A-to-D
conversion, into the device Temp register. This Temp register can be
read at any time by a controller on the I
2
C-bus. Reading
temperature data does not affect the conversion in progress during
the read operation.
The device can be set to operate in either mode: normal or
shut-down. In normal operation mode, the temp-to-digital conversion
is executed every 100 ms and the Temp register is updated at the
end of each conversion. In shut-down mode, the device becomes
idle, data conversion is disabled and the Temp register holds the
latest result; however, the device I
2
C interface is still active and
register write/ read operation can be performed. The device
operation mode is controllable by programming bit B0 of the
configuration register. The temperature conversion is initiated when
the device is powered-up or put back into normal mode from
shut-down.
In addition, at the end of each conversion in normal mode, the
temperature data (or Temp) in the Temp register is automatically
compared with the over-temp shut-down threshold data (or Tos)
stored in the Tos register, and the hysteresis data (or Thyst) stored
in the Thyst register, in order to set the state of the device OS output
accordingly. The device Tos and Thyst registers are write/read
capable, and both operate with 9-bit 2’s complement digital data.
To match with this 9-bit operation, the temp register uses only the
9 MSB bits of its 11-bit data for the comparison.
The way that the OS output responds to the comparison operation
depends upon the OS operation mode selected by configuration
bit B1, and the user-defined fault queue defined by configuration
bits B3 and B4.
In OS comparator mode, the OS output behaves like a thermostat. It
becomes active when the Temp exceeds the Tos, and is reset when
the Temp drops below the Thyst. Reading the device registers or
putting the device into shut-down does not change the state of the
OS output. The OS output in this case can be used to control
cooling fans or thermal switches.
In OS interrupt mode, the OS output is used for thermal interruption.
When the device is powered-up, the OS output is first activated only
when the Temp exceeds the Tos; then it remains active indefinitely
until being reset by a read of any register. Once the OS output has
been activated by crossing Tos and then reset, it can be activated
again only when the Temp drops below the Thyst; then again, it
remains active indefinitely until being reset by a read of any register.
The OS interrupt operation would be continued in this sequence:
Tos trip, Reset, Thyst trip, Reset, Tos trip, Reset, Thyst trip, Reset,
…
Putting the device into shut-down mode also resets the OS output.
In both cases, comparator mode and interrupt mode, the OS output
is activated only if a number of consecutive faults, defined by the
device fault queue, has been met. The fault queue is programmable
and stored in the two bits, B3 and B4, of the Configuration register.
Also, the OS output active state is selectable as HIGH or LOW by
setting accordingly the configuration register bit B2.
At power-up, the device is put into normal operation mode, the Tos
is set to 80
°
C, the Thyst is set to 75
°
C, the OS active state is
selected LOW and the fault queue is equal to 1. The temp reading
data is not available until the first conversion is completed in about
100 ms.
The OS response to the temperature is illustrated in Figure 5.
SL01392
Temp
*
*
*
POWER-UP
TIME
OS RESET
OS ACTIVE
OS OUTPUT IN INTERRUPT MODE
OS OUTPUT IN COMPARATOR MODE
OS RESET
OS ACTIVE
Tos
Thyst
READING TEMPERATURE & LIMITS
= OS is reset by either reading register or putting the device in shutdown.
Assumed that the fault queue is met at each Tos and Thyst crossing point.
Figure 5. OS response to temperature.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM75AD | 制造商:NXP Semiconductors 功能描述: |
| LM75AD,112 | 功能描述:板上安裝溫度傳感器 I2C LOCAL +/- 2OC TS RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)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(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| LM75AD,118 | 功能描述:板上安裝溫度傳感器 I2C LOCAL +/- 2OC TS RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準(zhǔn)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(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor |
| LM75AD.112 | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:Digital temperature sensor and thermal watchdog |
| LM75AD/G-T | 功能描述:IC I2C TEMP SNSR/WATCHDOG 8-SOIC RoHS:是 類別:集成電路 (IC) >> PMIC - 熱管理 系列:- 標(biāo)準(zhǔn)包裝:1 系列:- 功能:溫度監(jiān)控系統(tǒng)（傳感器） 傳感器類型:內(nèi)部和外部 感應(yīng)溫度:-40°C ~ 125°C，外部傳感器 精確度:±2.5°C 本地（最大值），±5°C 遠(yuǎn)程（最大值） 拓?fù)?ADC，比較器，寄存器庫 輸出類型:2 線 SMBus? 輸出警報(bào):無 輸出風(fēng)扇:無 電源電壓:2.7 V ~ 5.5 V 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-8 供應(yīng)商設(shè)備封裝:SOT-23-8 包裝:Digi-Reel® 其它名稱:296-22675-6 |
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