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参数资料
| 型号： | EVAL-AD7356EDZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 6/21页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL AD7356 |
| 标准包装： | 1 |
| ADC 的数量： | 2 |
| 位数： | 12 |
| 采样率（每秒）： | 5M |
| 数据接口： | 串行 |
| 输入范围： | ±VREF/2 |
| 在以下条件下的电源（标准）： | 36mW @ 5MSPS |
| 工作温度： | -40°C ~ 85°C |
| 已用 IC / 零件： | AD7356 |
| 已供物品： | 板，CD |
AD7356
Rev. A | Page 13 of 20
For ac applications, removing high frequency components from
the analog input signal is recommended by the use of an RC
low-pass filter on the analog input pins. In applications where
harmonic distortion and signal-to-noise ratio are critical, the
analog input should be driven from a low impedance source.
Large source impedances significantly affect the ac perfor-
mance of the ADC and may necessitate the use of an input
buffer amplifier. The choice of the op amp is a function of the
particular application.
When no amplifier is used to drive the analog input, limit
the source impedance to low values. The maximum source
impedance depends on the amount of THD that can be
tolerated. THD increases as the source impedance increases
and performance degrades. Figure 17 shows a graph of the
THD vs. the analog input signal frequency for different source
impedances.
–87
–85
–83
–81
–79
–77
–75
–73
–71
–69
–67
–65
100
200
1000
1500
2000
2500
T
HD
(
d
B
)
FREQUENCY (kHz)
06
50
5-
02
6
100
50
33
10
Figure 17. THD vs. Analog Input Signal Frequency for Various Source
Impedances
Figure 18 shows a graph of the THD vs. the analog input
frequency while sampling at 5 MSPS. In this case, the source
impedance is 33 Ω.
–90
–86
–82
–78
–74
–70
–66
0
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
T
HD
(
d
B
)
ANALOG INPUT FREQUENCY (kHz)
07
04
4-
02
9
Figure 18. THD vs. Analog Input Frequency
ANALOG INPUTS
Differential signals have some benefits over single-ended
signals, including noise immunity based on the devices
common-mode rejection and improvements in distortion
performance. Figure 19 defines the fully differential input
of the AD7356.
VIN+
AD7356*
VIN–
VREF p-p
*ADDITIONAL PINS OMITTED FOR CLARITY.
COMMON-MODE
VOLTAGE
06
505
-0
34
Figure 19. Differential Input Definition
The amplitude of the differential signal is the difference
between the signals applied to the VIN+ and VIN pins in
each differential pair (VIN+ VIN). VIN+ and VIN should be
simultaneously driven by two signals each of amplitude (VREF)
that are 180° out of phase. This amplitude of the differential
signal is, therefore, –VREF to +VREF peak-to-peak regardless of
the common mode (CM).
CM is the average of the two signals and is, therefore, the
voltage on which the two inputs are centered.
CM = (VIN+ + VIN)/2
This results in the span of each input being CM ± VREF/2. This
voltage has to be set up externally. When setting up the CM,
ensure that VIN+ and VIN remain within GND/VDD. When
a conversion takes place, CM is rejected, resulting in a virtually
noise-free signal of amplitude, –VREF to +VREF, corresponding
to the digital codes of 0 to 4095 for the AD7356.
DRIVING DIFFERENTIAL INPUTS
Differential operation requires VIN+ and VIN to be driven
simultaneously with two equal signals that are 180° out of phase.
Because not all applications have a signal preconditioned for
differential operation, there is often a need to perform a single-
ended-to-differential conversion.
Differential Amplifier
An ideal method of applying differential drive to the AD7356
is to use a differential amplifier such as the AD8138. This part
can be used as a single-ended-to-differential amplifier or as a
differential-to-differential amplifier. The AD8138 also provides
can be used as a single-ended-to-differential amplifier. The
positive and negative outputs of the AD8138 are connected to
the respective inputs on the ADC via a pair of series resistors
to minimize the effects of switched capacitance on the front
end of the ADC. The architecture of the AD8138 results in
outputs that are very highly balanced over a wide frequency
range without requiring tightly matched external components.
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相关代理商/技术参数 |
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|---|---|
| EVAL-AD7357EDZ | 功能描述:BOARD EVAL FOR AD7357 RoHS:是 类别:编程器，开发系统 >> 评估板 - 模数转换器 (ADC) 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率（每秒）:94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源（标准）:- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，软件 |
| EVAL-AD7366CBZ | 功能描述:BOARD EVALUATION FOR AD7366 RoHS:是 类别:编程器，开发系统 >> 评估板 - 模数转换器 (ADC) 系列:iCMOS® 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率（每秒）:94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源（标准）:- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，软件 |
| EVAL-AD7366SDZ | 功能描述:BOARD EVAL FOR AD7366 RoHS:是 类别:编程器，开发系统 >> 评估板 - 模数转换器 (ADC) 系列:iCMOS® 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:- ADC 的数量:1 位数:12 采样率（每秒）:94.4k 数据接口:USB 输入范围:±VREF/2 在以下条件下的电源（标准）:- 工作温度:-40°C ~ 85°C 已用 IC / 零件:MAX11645 已供物品:板，软件 |
| EVAL-AD7367CBZ | 制造商:AD 制造商全称:Analog Devices 功能描述:True Bipolar Input, Dual 1 レs, 12-/14-Bit, 2-Channel SAR ADCs |
| EVAL-AD7367SDZ | 功能描述:数据转换 IC 开发工具 EVALUATION CONTROL BOARD I.C. RoHS:否 制造商:Texas Instruments 产品:Demonstration Kits 类型:ADC 工具用于评估:ADS130E08 接口类型:SPI 工作电源电压:- 6 V to + 6 V |
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