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參數(shù)資料
| 型號： | EVAL-AD7191EBZ |
| 廠商： | Analog Devices Inc |
| 文件頁數(shù)： | 13/21頁 |
| 文件大?。?/td> | 0K |
| 描述： | BOARD EVAL FOR AD7191 |
| 設計資源： | EVAL-AD7191 Schematic AD7191 Gerber Files |
| 標準包裝： | 1 |
| ADC 的數(shù)量： | 1 |
| 位數(shù)： | 24 |
| 采樣率（每秒）： | 120 |
| 數(shù)據(jù)接口： | MICROWIRE?，QSPI?，串行，SPI? |
| 輸入范圍： | ±5 V |
| 工作溫度： | -40°C ~ 105°C |
| 已用 IC / 零件： | AD7191 |
| 已供物品： | 板 |
AD7191
Rev. A | Page 19 of 20
APPLICATIONS INFORMATION
The AD7191 provides a low-cost, high resolution analog-to-
digital function. Because the analog-to-digital function is
provided by a ∑-Δ architecture, the part is more immune to
noisy environments, making it ideal for use in sensor
measurement and industrial and process control applications.
WEIGH SCALES
Figure 24 shows the AD7191 being used in a weigh scale
application. The load cell is arranged in a bridge network and
gives a differential output voltage between its OUT+ and OUT–
terminals. Assuming a 5 V excitation voltage, the full-scale
output range from the transducer is 10 mV when the sensitivity
is 2 mV/V. The excitation voltage for the bridge can be used to
directly provide the reference for the ADC because the reference
input range includes the supply voltage.
A second advantage of using the AD7191 in transducer-based
applications is that the bridge power-down switch can be fully
utilized in low power applications. The bridge power-down
switch is connected in series with the low side of the bridge. In
normal operation, the switch is closed and measurements can
be taken. In applications where power is of concern, the
AD7191 can be placed in power-down mode, thus significantly
reducing the power consumed in the application. In addition,
the bridge power-down switch is opened while in power-down
mode, thus avoiding unnecessary power consumption by the
front-end transducer. When the part is taken out of power-
down mode and the bridge power-down switch is closed, the
user should ensure that the front-end circuitry is fully settled
before attempting a read from the AD7191.
The load cell has an offset or TARE associated with it. This
TARE is the main component of the system offset (load cell plus
ADC) and is of a magnitude similar to the full-scale signal from
the load cell. For this reason, a system calibration that calibrates
the offset and full-scale error of the ADC plus the load cell is
required. A microprocessor can be used to perform the
calibrations. The offset (the conversion result from the AD7191
when no load is applied to the load cell) and the full-scale error
(the conversion result from the ADC when the maximum load
is applied to the load cell) must be determined. Subsequent
conversions from the AD7191 are then corrected using the
offset and full-scale coefficients calculated from the above
calibrations.
EMI RECOMMENDATIONS
For simplicity, the EMI filters are not included in Figure 24.
However, an R-C antialias filter should be included on each
analog input. This filter is needed because the on-chip digital
filter does not provide any rejection around MCLK/8 or
multiples of this frequency. Suitable values are a 100 Ω resistor in
series with each analog input, a 0.1 μF capacitor from AIN(+) to
AIN(), and 0.01 μF capacitors from AIN(+)/AIN() to AGND
(see Figure 23).
0.01F
100
0.1F
AD7191
100
AIN(+): AIN1 OR AIN3
AIN(–): AIN2 OR AIN4
0.01F
08
16
3-
01
8
Figure 23. External Filtering Connections
MUX
AD7191
AIN1
DOUT/RDY
SCLK
PDOWN
CHAN
CLKSEL
PGA2
REFERENCE
DETECT
PGA1
AGND
5V
IN+
OUT+
IN–
OUT–
REFIN(+)
REFIN(–)
BPDSW
AVDD
DVDD
DGND
AIN2
AIN3
AIN4
MCLK1
MCLK2
ODR2 ODR1 TEMP
TEMPERATURE
SENSOR
CLOCK
CIRCUITRY
PGA
SERIAL
INTERFACE
AND CONTROL
LOGIC
Σ-Δ
ADC
08
16
3-
0
17
Figure 24. Typical Application (Weigh Scale)
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| EVAL-AD7192EBZ | 功能描述:BOARD EVAL FOR AD7192 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數(shù)轉換器 (ADC) 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- ADC 的數(shù)量:1 位數(shù):12 采樣率（每秒）:94.4k 數(shù)據(jù)接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標準）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7192EBZ | 制造商:Analog Devices 功能描述:EVAL BOARD, AD7192 24BIT ADC |
| EVAL-AD7193EBZ | 功能描述:EVAL BOARD FOR AD7193 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數(shù)轉換器 (ADC) 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- ADC 的數(shù)量:1 位數(shù):12 采樣率（每秒）:94.4k 數(shù)據(jù)接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標準）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7194EBZ | 功能描述:EVAL BOARD FOR AD7194 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估板 - 模數(shù)轉換器 (ADC) 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- ADC 的數(shù)量:1 位數(shù):12 采樣率（每秒）:94.4k 數(shù)據(jù)接口:USB 輸入范圍:±VREF/2 在以下條件下的電源（標準）:- 工作溫度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，軟件 |
| EVAL-AD7195EBZ | 功能描述:BOARD EVAL FOR AD7195 RoHS:是 類別:編程器，開發(fā)系統(tǒng) >> 評估演示板和套件 系列:- 標準包裝:1 系列:- 主要目的:電信，線路接口單元（LIU） 嵌入式:- 已用 IC / 零件:IDT82V2081 主要屬性:T1/J1/E1 LIU 次要屬性:- 已供物品:板，電源，線纜，CD 其它名稱:82EBV2081 |
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