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参数资料
| 型号： | LMP90079MH/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 模拟信号调理 |
| 英文描述： | SPECIALTY ANALOG CIRCUIT, PDSO28 |
| 封装： | LEAD FREE, PLASTIC, MO-153, TSSOP-28 |
| 文件页数： | 24/62页 |
| 文件大小： | 1721K |
| 代理商： | LMP90079MH/NOPB |
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16.4 SENSOR INTERFACE
The LMP90080/LMP90078 contains two excitation currents
(IB1 & IB2) for sourcing external sensors, and the LMP900xx
contain two burnout currents for sensor diagnostics. They are
described in the next sections.
16.4.1 IB1 & IB2 - Excitation Currents (LMP90080/
LMP90078)
IB1 and IB2 can be used for providing currents to external
sensors, such as RTDs or bridge sensors. 100A to 1000A,
in steps of 100A, can be sourced by programming the
ADC_AUXCN: RTD_CUR_SEL bits.
Refer to Section 17.6.1 3–Wire RTD to see how IB1 and IB2
can be used to source a 3-wire RTD.
16.4.2 Burnout Currents
As shown in Figure 16, the LMP900xx contains two internal
10 A burnout current sources, one sourcing current from VA
to VINP, and the other sinking current from VINN to ground.
These currents are used for sensor diagnostics and can be
enabled for each channel using the CHx_INPUTCN:
BURNOUT_EN bit.
30169780
FIGURE 16. Burnout Currents
Burnout Current Injection:
Burnout currents are injected differently depending on the
channel scan mode selected.
When BURNOUT_EN = 1 and the device is operating in
ScanMode0, 1, or 2, the burnout currents are injected into all
the channels for which the BURNOUT_EN bit is selected.
This will cause problems and hence in this mode, more than
one channel should not have its BURNOUT_EN bit selected.
Also, the burnout current will interfere with the signal and in-
troduce a fixed error depending on the particular external
sensor.
When BURNOUT_EN = 1 and the device is operating in
ScanMode3, burnout currents are injected into the last sam-
pled channel on a cyclical basis (Figure 17). In this mode,
burnout currents injection is truly done in the background
without affecting the accuracy of the on-going conversion.
Operating in this mode is recommended.
30169781
FIGURE 17. Burnout Currents Injection for ScanMode3
16.4.3 Sensor Diagnostic Flags
Burnout currents can be used to verify that an external sensor
is still operational before attempting to make measurements
on that channel. A non-operational sensor means that there
is a possibility the connection between the sensor and the
LMP900xx is open circuited, short circuited, shorted to VA or
GND, overloaded, or the reference may be absent. The sen-
sor diagnostic flags diagram can be seen in Figure 18.
www.national.com
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LMP90080/LMP90079/LMP90078/LMP90077
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LMP90079MHX/NOPB | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| LMP90080 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Sensor AFE System: Multi-Channel, Low-Power 16-Bit |
| LMP90080MH/NOPB | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| LMP90080MHE/NOPB | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| LMP90080MHX/NOPB | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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