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参数资料
| 型号： | LMP90078MHX/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： | 22/62页 |
| 文件大小： | 1721K |
| 代理商： | LMP90078MHX/NOPB |
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the conversion, the CHx_SCAL_OFFSET register is
filled-in with the System Calibration Offset coefficient.
4.
The System Calibration Offset Coefficient Determination
mode is automatically exited.
5.
The computed calibration coefficient is accurate only to
the effective resolution of the device and will probably
contain some noise. The noise factor can be minimized
by computing over many times, averaging (externally)
and putting the resultant value back into the register.
Alternatively, select the output data rate to be 26.83 sps
or 1.67 sps.
System Calibration Gain Coefficient Determination mode
1.
Repeat the System Calibration Offset Coefficient
Determination to calibrate the System offset for the
channel.
2.
Apply the system reference-scale condition to the
channel CH0/CH1/CH2/CH3.
3.
In the CHx_SCAL_GAIN register, program the expected
(desired) system-calibrated output code for this condition
in 16-bit unsigned format.
4.
Enter the System Calibration Gain Coefficient
Determination mode by programming 0x3 in the
SCALCN register.
5.
LMP900xx starts a fresh conversion at the selected
output data rate for the channel. At the end of the
conversion, the CHx_SCAL_GAIN is filled-in (or
overwritten) with the System Calibration Gain coefficient.
6.
The System Calibration Gain Coefficient Determination
mode is automatically exited.
7.
The computed calibration coefficient is accurate only to
the effective resolution of the device and will probably
contain some noise. The noise factor can be minimized
by computing over many times, averaging (externally)
and putting the resultant value back into the register.
Alternatively, select the output data rate to be 26.83 sps
or 1.67 sps.
Post-calibration Scaling
LMP900xx allows scaling (multiplication and shifting) for the
System Calibrated result. This eases downstream process-
ing, if any. Multiplication is done using the System Calibration
Scaling Coefficient in the CHx_SCAL_SCALING register and
shifting is done using the System Calibration Bits Selector in
the CHx_SCAL_BITS_SELECTOR register.
The System Calibration Bits Selector value should ideally be
the logarithm (to the base 2) of the System Calibration Scaling
Coefficient value.
There are four distinct sets of System Calibration Scaling and
System Calibration Bits Selector Registers for use with CH0-
CH3. CH4-CH6 reuse the registers of CH0-CH2, respectively.
A data-flow diagram of these coefficients can be seen in Fig-
30169742
FIGURE 15. Post-calibration Scaling Data-Flow Diagram
16.3 CHANNELS SCAN MODE
There are four scan modes. These scan modes are selected
using the CH_SCAN: CH_SCAN_SEL bit. The first scanned
channel is FIRST_CH, and the last scanned channel is
LAST_CH; they are both located in the CH_SCAN register.
The CH_SCAN register is double buffered. That is, user in-
puts are stored in a slave buffer until the start of the next
conversion during which time they are transferred to the mas-
ter buffer. Once the slave buffer is written, subsequent up-
dates are disregarded until a transfer to the master buffer
happens. Hence, it may be appropriate to check the
CH_SCAN_NRDY bit before programming the CH_SCAN
register.
ScanMode0: Single-Channel Continuous Conversion
LMP900xx continuously converts the selected FIRST_CH.
Do not operate in this scan mode if gain
≥ 16 and the LM-
P900xx is running in background calibration modes Bg-
calMode1 or BgcalMode2. If this is the case, then it is more
suitable to operate the device in ScanMode2 instead.
ScanMode1: Multiple-Channels Single Scan
LMP900xx converts one or more channels starting from
FIRST_CH to LAST_CH, and then enters the stand-by state.
ScanMode2: Multiple-Channels Continuous Scan
LMP900xx continuously converts one or more channels start-
ing from FIRST_CH to LAST_CH, and then it repeats this
process.
ScanMode3: Multiple-Channels Continuous Scan with
Burnout Currents
This mode is the same as ScanMode2 except that the burnout
current is provided in a serially scanned fashion (injected in a
channel after it has undergone a conversion). Thus it avoids
burnout current injection from interfering with the conversion
result for the channel.
The sensor diagnostic burnout currents are available for all
four scan modes. The burnout current is further gated by the
BURNOUT_EN bit for each channel. ScanMode3 is the only
mode that scans multiple channels while injecting burnout
currents without interfering with the signal. This is described
in details in Section 16.4.2 Burnout Currents.
29
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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 |
|---|---|
| LMP90079 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Sensor AFE System: Multi-Channel, Low-Power 16-Bit |
| LMP90079MH/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 |
| LMP90079MHE/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 |
| 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 |
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