參數(shù)資料
型號(hào)： LM81CIMTX-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)： 16/33頁(yè)
文件大?。?/td> 414K
代理商： LM81CIMTX-3
Functional Description
(Continued)
equal to its LOW limit will cause a flag to be set in its
Interrupt Status Register. This flag will activate the INT
output when its mask bit is set low. Mask bits are found in the
Interrupt Mask Registers.
5.0 LAYOUT AND GROUNDING
A separate, low-impedance ground plane for analog ground,
which provides a ground point for both GND pins, voltage
dividers and other analog components, will provide best
performance but is not mandatory. Analog components such
as voltage dividers should be located physically as close as
possible to the LM81.
The power supply bypass, the parallel combination of 10 μF
(electrolytic or tantalum) and 0.1 μF (ceramic) bypass
capacitors connected between pin 12 and ground, should
also be located as close as possible to the LM81.
6.0 FAN INPUTS
The FAN1 and FAN2 inputs accept signals from fans
equipped with tachometer outputs. These are logic-level
inputs with an approximate threshold of V
+
/2. Signal
conditioning in the LM81 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 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 LM81 is off,
the LM81 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
inherently 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:
with
pull-up
resistors
Note that Fan 1 and Fan 2 Divisors are programmable via
the VID/Fan Divisor Register.
Fan tachometer outputs that provide one pulse per
revolution should use a divisor setting twice that of outputs
that provide two pulses per revolution. For example, a 4400
RPM fan that provides one pulse per revolution should have
the divisor set to 4 such that the nominal counter output is
153.
L
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16
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LM81CIMTX-32 制造商:NSC 制造商全稱(chēng):National Semiconductor 功能描述:Serial Interface ACPI-Compatible Microprocessor System
LM81DH12 功能描述:基本/快動(dòng)開(kāi)關(guān) Foot Switch RoHS:否 制造商:Omron Electronics 觸點(diǎn)形式:SPDT 執(zhí)行器:Lever 電流額定值:5 A 電壓額定值 AC:250 V 電壓額定值 DC:30 V 功率額定值: 工作力:120 g IP 等級(jí):IP 67 NEMA 額定值: 端接類(lèi)型:Wire 安裝:Panel
LM8-1M.5M.1 制造商:Banner Engineering 功能描述:LM8-1M.5M.1 LOGIC MOD MULTIBM
LM81-S 功能描述:基本/快動(dòng)開(kāi)關(guān) Foot Switch RoHS:否 制造商:Omron Electronics 觸點(diǎn)形式:SPDT 執(zhí)行器:Lever 電流額定值:5 A 電壓額定值 AC:250 V 電壓額定值 DC:30 V 功率額定值: 工作力:120 g IP 等級(jí):IP 67 NEMA 額定值: 端接類(lèi)型:Wire 安裝:Panel
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