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參數(shù)資料
| 型號： | 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) |
| 文件頁數(shù)： | 10/33頁 |
| 文件大小： | 414K |
| 代理商： | LM81CIMTX-3 |
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Test Circuit
Functional Description
1.0 GENERAL DESCRIPTION
The LM81 provides 6 analog inputs, a temperature sensor, a
Delta-Sigma ADC (Analog-to-Digital Converter), a DAC
output, 2 fan speed counters, WATCHDOG registers, and a
variety of inputs and outputs on a single chip. A two wire
Serial Bus interface is included. The LM81 performs power
supply, temperature, fan control and fan monitoring for
personal computers.
The analog inputs are useful for monitoring several power
supplies present in a typical computer. The LM81 includes
internal resistor dividers that scale and/or offset external
Vccp, +2.5V, +3.3V, +5.0V and +12V power supply voltages
to a 3/4 scale nominal ADC output. The LM81 ADC then
continuously converts the scaled inputs to 8-bit digital words.
Measurement of negative voltages (such as -5V and -12V
power supplies) can be accommodated with an external
resistor divider applied to the Vccp2 input. Temperature is
converted to a 9-bit or 12-bit two’s-complement digital word
with a 0.5C LSB or 0.0625C LSB, respectively.
Fan inputs measure the period of tachometer pulses from
the fans, providing a higher count for lower fan speeds. The
fan inputs are Schmitt-Trigger digital inputs with an
acceptable range of 0V to V
+
and a transition level of
approximately V
+
/2. Full scale fan counts are 255 (8-bit
counter) and this represents a stopped or very slow fan.
Nominal
speeds,
based
on
programmable from 1100 to 8800 RPM on FAN1 and FAN2.
Schmitt-Trigger input circuitry is included to accommodate
slow rise and fall times. A 0V to 1.25V DAC output voltage
range can be used for control of fan speed.
The LM81 has several internal registers, as shown in Figure
4 Table 1 and Section 13.0 These include:
Configuration
Register:
configuration.
Interrupt Status Registers:
status of each WATCHDOG limit or Interrupt event.
Interrupt
Mask
Registers:
individual Interrupt sources, as well as separate masking
for each of the two hardware Interrupt outputs.
a
count
of
153,
are
Provides
control
and
Two registers to provide
Allows
masking
of
CI Clear Register:
pulse on the chassis intrusion pin (CI).
VID/Fan Divisor Register:
state of the VID0-VID3 input lines and the divisor bits for
FAN1 and FAN2 inputs.
Serial Bus Address Register:
address. At power on it assumes the default value of
01011XX binary, and can be altered by the state of A0
and A1.
VID4 Register:
Contains the state of the VID4 input.
Temperature Configuration Register:
interrupt mode and contains the 0.5C LSB of the
temperature reading.
Extended Mode Registers:
Extended Mode which includes the LSBs of the 12-bit
temperature reading, T_CRIT, and T
HYST
Value RAM:
The DAC digital input, monitoring results
(temperature, voltages, fan counts), WATCHDOG limits,
and Company/Stepping IDs are all contained in the Value
RAM. The Value RAM consists of a total of 34 bytes,
addresses 15h - 3Fh, containing:
— byte 1 at address 15h a manufacturers test register
— locations 16h - 18h are unassigned and do not have
associated registers
— byte 2 at address 19h contains the DAC Data Register
— locations 1Ah - 1Fh are unassigned and do not have
associated registers
— the next 10 bytes at addresses 20h -29h contain all of
the results, with address 26h reserved
— the next 18 bytes at addresses 2Bh-3Ch are the
WATCHDOG limits
— the last 2 bytes at addresses 3Eh and 3Fh contain the
Company ID and Stepping ID numbers, respectively
When the LM81 is started, it cycles through each
measurement in sequence, and it continuously loops
through the sequence approximately once every 400 ms.
Each measured value is compared to values stored in
WATCHDOG, or Limit registers. When the measured value
violates the programmed limit the LM81 will set a
corresponding Interrupt in the Interrupt Status Registers.
The hardware Interrupt line INT is fully programmable with
Allows transmitting a 20 ms low
This register contains the
Contains the Serial Bus
Selects the
Enable and control the
DS100072-6
FIGURE 3. Digital Output Load Test Circuitry
L
www.national.com
10
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM81CIMTX-3/NOPB | 功能描述:監(jiān)控電路 RoHS:否 制造商:STMicroelectronics 監(jiān)測電壓數(shù): 監(jiān)測電壓: 欠電壓閾值: 過電壓閾值: 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 |
| LM81CIMTX-32 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Serial Interface ACPI-Compatible Microprocessor System |
| LM81DH12 | 功能描述:基本/快動開關(guān) Foot Switch RoHS:否 制造商:Omron Electronics 觸點形式: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:IP 67 NEMA 額定值: 端接類型: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/快動開關(guān) Foot Switch RoHS:否 制造商:Omron Electronics 觸點形式: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:IP 67 NEMA 額定值: 端接類型:Wire 安裝:Panel |
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