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参数资料
| 型号： | LM40CIMT/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 模拟信号调理 |
| 英文描述： | SPECIALTY ANALOG CIRCUIT, PDSO14 |
| 封装： | MO-153AB, TSSOP-14 |
| 文件页数： | 2/27页 |
| 文件大小： | 369K |
| 代理商： | LM40CIMT/NOPB |
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Typical Performance Characteristics
Remote Diode Temperature Reading Sensitivity to Diode
Filter Capacitance
Thermal Diode Capacitor or PCB Leakage Current Effect
on Remote Diode Temperature Reading
20068421
20068422
1.0 Functional Description
The LM40 hardware monitor measures up to 3 temperature
zones and 5 power supply voltages. The LM40 uses a
V
be
temperature sensing method. A differential voltage, repre-
senting temperature, is digitized using a Sigma-Delta analog
to digital converter. Internal scaling resistors allow direct
measurement of the +1.6V, +2.5V, +5V, +3.3V and +12V
power supply inputs. The digitized data can be retrieved over
a simple single-wire interface called SensorPath. Sensor-
Path has been defined by National Semiconductor and is
optimized for hardware monitoring. National offers a royalty-
free license in connection with its intellectual property rights
in the SensorPath bus.
The LM40 has one address pin to allow up to two LM40s to
be connected to one SensorPath bus. The physical interface
of SensorPath’s SWD signal is identical to the familiar indus-
try standard SMBus SMBDAT signal. The digital information
is encoded in the pulse width of the signal being transmitted.
Every bit can be synchronized by the master simplifying the
implementation of the master when using a micro-controller.
For micro-controller’s with greater functionality an asynchro-
nous attention signal can be transmitted by the LM40 to
interrupt the micro-controller and notify it that temperature/
voltage data has been updated in the readout registers.
To optimize the LM40’s power consumption to the system
requirements, the LM40 has a shutdown mode and supports
multiple conversion rates.
1.1 SensorPath BUS SWD
SWD is the Single Wire Data line used for communication.
SensorPath uses 3.3V single-ended signaling, with a pull-up
resistor and open-drain low-side drive (see Figure 3). For
timing purposes SensorPath is designed for capacitive loads
(C
L) of up to 400pF. Note that in many cases a 3.3V standby
rail of the PC will be used as a power supply for both the
sensor and the master. Logic high and low voltage levels for
SWD are TTL compatible. The master may provide an inter-
nal pull-up resistor. In this case the external resistor is not
needed. The minimum value of the pull-up resistor must take
into account the maximum allowable output load current of
4mA.
1.2 SensorPath BIT SIGNALING
Signals are transmitted over SensorPath using pulse-width
encoding. There are five types of "bit signals":
Data Bit 0
Data Bit 1
Start Bit
Attention Request
Reset
All the "bit signals" involve driving the bus to a low level. The
duration of the low level differentiates between the different
"bit-signals". Each "bit signal" has a fixed pulse width. Sen-
sorPath supports a Bus Reset Operation and Clock Training
sequence that allows the slave device to synchronize its
internal clock rate to the master. Since the LM40 meets the
±15% timing requirements of SensorPath, the LM40 does
not require the Clock Training sequence and does not sup-
port this feature. This section defines the "bit signal" behav-
ior in all the modes. Please refer to the timing diagrams in
while going through this section. Note that the timing dia-
grams for the different types of "bit signals" are shown
together to better highlight the timing relationships between
them. However, the different types of "bit signals" appear on
SWD at different points in time. These timing diagrams show
the signals as driven by the master and the LM40 slave as
well as the signal as seen when probing SWD. Signal labels
20068407
FIGURE 3. SensorPath SWD simplified schematic
LM40
www.national.com
10
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相关代理商/技术参数 |
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| LM40CIMTX/NOPB | 功能描述:IC HARDWARE MONITOR 14-TSSOP RoHS:是 类别:集成电路 (IC) >> 接口 - 专用 系列:- 标准包装:3,000 系列:- 应用:PDA，便携式音频/视频，智能电话 接口:I²C，2 线串口 电源电压:1.65 V ~ 3.6 V 封装/外壳:24-WQFN 裸露焊盘 供应商设备封装:24-QFN 裸露焊盘（4x4） 包装:带卷 (TR) 安装类型:表面贴装 产品目录页面:1015 (CN2011-ZH PDF) 其它名称:296-25223-2 |
| LM40F1WE26-A | 制造商:CEC Industries 功能描述:LED BULB, MEDIUM SCREW/E26, AMBER, 1W, Lamp Base Type:Medium Screw / E26, LED Co |
| LM40F1WE26-B | 制造商:CEC Industries 功能描述:LED BULB, MEDIUM SCREW/E26, BLUE, 1W, Lamp Base Type:Medium Screw / E26, LED Col |
| LM40F1WE26-G | 制造商:CEC Industries 功能描述:LED BULB, MEDIUM SCREW/E26, GREEN, 1W, Lamp Base Type:Medium Screw / E26, LED Color:Green, Bulb Size:G-40, Power Rating:1W, Wavelength Typ:525nm, Average Bulb Life:240h, Supply Voltage:240V, Current Rating:100mA, Beam Divergence:360, RoHS Compliant: Yes |
| LM40F1WE26-R | 制造商:CEC Industries 功能描述:LED BULB, MEDIUM SCREW/E26, RED, 1W, Lamp Base Type:Medium Screw / E26, LED Color:Red, Bulb Size:G-40, Power Rating:1W, Wavelength Typ:629nm, Average Bulb Life:240h, Supply Voltage:240V, Current Rating:100mA, Beam Divergence:360 , RoHS Compliant: Yes |
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