參數(shù)資料
型號： LM87
廠商： National Semiconductor Corporation
英文描述： Serial Interface System Hardware Monitor with Remote Diode Temperature Sensing
中文描述： 串行接口系統(tǒng)硬件監(jiān)控與遠程二極管溫度傳感器
文件頁數(shù)： 16/32頁
文件大小： 470K
代理商： LM87
Functional Description
(Continued)
Counts are based on 2 pulses per revolution tachometer
outputs.
RPM
Time per Revolution
Counts for “Divide by 2”
(Default) in Decimal
153 counts
219 counts
255 counts
(maximum counts)
Comments
4400
3080
2640
13.64 ms
19.48 ms
22.73 ms
Typical RPM
70% RPM
60% RPM
Mode Select
Nominal RPM
Time per Revolution
Counts for the
Given Speed in Decimal
153
153
153
153
70% RPM
Time per Revolution
for 70% RPM
9.74 ms
19.48 ms
38.96 ms
77.92 ms
Divide by 1
Divide by 2
Divide by 4
Divide by 8
8800
4400
2200
1100
6.82 ms
13.64 ms
27.27 ms
54.54 ms
6160
3080
1540
770
7.0 DAC OUTPUT
The LM87 provides an 8-bit DAC (Digital-to-Analog Con-
verter) with an output range of 0 to 2.5 volts (9.80 mV LSB).
This DAC can be used in any way, but in most applications of
the LM87 the DAC will be used for fan control. Typically the
DAC output would be amplified to provide the up to 12 volt
drive required by the fan. At power-on the DAC provides full
output, insuring that full fan speed is the default condition.
Care should be taken such that the analog circuitry tied to
this pin does not drive this pin above 2.5 V. Doing so will
place the LM87 in NAND tree test mode which will make all
pins inputs. After the first SMBus communication with the
LM87, it will leave NAND tree test mode and all inputs/
outputs will function normally.
Fans do not start reliably at reduced voltages, so operation
at a reduced voltage should be preceded by a brief (typically
10099512
(a) Fan with Tach Pull-Up to +5V
10099513
(b) Fan with Tach Pull-Up to +12V, or Totem-Pole Output
and Resistor Attenuator
10099514
(c) Fan with Tach Pull-Up to +12V and Diode Clamp
10099515
(d) Fan with Strong Tach Pull-Up or Totem Pole Output
and Diode Clamp
FIGURE 7. Alternatives for Fan Inputs
L
www.national.com
16
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相關代理商/技術參數(shù)
參數(shù)描述
LM87CIMT 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
LM87CIMT 制造商:Texas Instruments 功能描述:HDW MON, 2 REMOTE TEMP SENS, SMD 制造商:Texas Instruments 功能描述:HDW MON, 2 REMOTE TEMP SENS, SMD; IC Output Type:Voltage; Sensing Accuracy Range: 3C; Sensing Temperature Min:-40C; Sensing Temperature Max:+125C; Supply Voltage Min:2.8V; Supply Voltage Max:3.8V; Sensor Case Style:TSSOP; No. of ;RoHS Compliant: Yes
LM87CIMT/NOPB 功能描述:板上安裝溫度傳感器 Hdw Mon & 2 Remote Temp Sens 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
LM87CIMTX 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
LM87CIMTX/NOPB 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
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