參數(shù)資料
型號(hào)： LM80CIMTX-3
英文描述： Single-Ended Data Acquisition System
中文描述： 單端數(shù)據(jù)采集系統(tǒng)
文件頁(yè)數(shù)： 14/29頁(yè)
文件大小： 409K
代理商： LM80CIMTX-3
Functional Description
(Continued)
6.0 FAN INPUTS
Inputs are provided for signals from fans equipped with
tachometer outputs. These are logic-level inputs with an
approximate threshold of V
+
/2. Signal conditioning in the
LM80 accommodates the slow rise and fall times typical of
fan tachometer outputs. The maximum input signal range is
0 to V
+
. In the event these inputs are supplied from fan
outputs which exceed 0 to V+, either resistive division or
diode clamping must be included to keep inputs within an
acceptable range, as shown in Figure 7 R2 is selected so
that it does not develop excessive error voltage due to input
leakage. R1 is selected based on R2 to provide a minimum
input of 2V and a maximum of V
+
. R1 should be as low as
possible to provide the maximum possible input up to V
+
for
best noise immunity. Alternatively, use a shunt reference or
zener diode to clamp the input level.
If fans can be powered while the power to the LM80 is off,
the LM80 inputs will provide diode clamping. Limit input
current to the Input Current at Any Pin specification shown in
the ABSOLUTE MAXIMUM RATINGS section. In most
cases, open collector outputs with pull-up resistors inher-
ently limit this current. If this maximum current could be
exceeded, either a larger pull up resistor should be used or
resistors connected in series with the fan inputs.
The Fan Inputs gate an internal 22.5 kHz oscillator for one
period of the Fan signal into an 8-bit counter (maximum
count = 255). The default divisor, located in the VID/Fan
Divisor Register, is set to 2 (choices are 1, 2, 4, and 8)
providing a nominal count of 153 for a 4400 rpm fan with two
pulses per revolution. Typical practice is to consider 70% of
normal RPM a fan failure, at which point the count will be
219.
Determine the fan count according to:
Note that Fan 1 and Fan 2 Divisors are programmable via
the Fan Divisor/RST_OUT/OS Register.
FAN1 and FAN2 inputs can also be programmed to be level
sensitive digital inputs.
Fans that provide only one pulse per revolution would re-
quire a divisor set twice as high as fans that provide two
pulses, thus maintaining a nominal fan count of 153. There-
fore the divisor should be set to 4 for a fan that provides 1
pulse per revolution with a nominal RPM of 4400.
L
www.national.com
14
相關(guān)PDF資料
PDF描述
LM80CIMTX-5 Single-Ended Data Acquisition System
LM8162
LM8164
LM8165
LM81CIMT-3 DATA ACQ SYSTEM|6-CHANNEL|8-BIT|TSSOP|24PIN|PLASTIC
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM80CIMTX-3 NOPB 制造商:Texas Instruments 功能描述:
LM80CIMTX-3/NOPB 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
LM80CIMTX-32 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Serial Interface ACPI-Compatible Microprocessor System Hardware Monitor
LM80CIMTX-5 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
LM80CIMTX-5/NOPB 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測(cè)電壓數(shù): 監(jiān)測(cè)電壓: 欠電壓閾值: 過(guò)電壓閾值: 輸出類型:Active Low, Open Drain 人工復(fù)位:Resettable 監(jiān)視器:No Watchdog 電池備用開(kāi)關(guān):No Backup 上電復(fù)位延遲（典型值）:10 s 電源電壓-最大:5.5 V 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:UDFN-6 封裝:Reel
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*