参数资料
| 型号： | AD684AQ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 7/8页 |
| 文件大小： | 0K |
| 描述： | IC AMP SAMPLE HOLD QUAD 16CDIP |
| 标准包装： | 1 |
| 放大器类型： | 采样和保持 |
| 电路数： | 4 |
| -3db带宽： | 4MHz |
| 电流 - 输入偏压： | 100nA |
| 电流 - 电源： | 18mA |
| 电流 - 输出 / 通道： | 5mA |
| 电压 - 电源，单路/双路(±)： | ±10.8 V ~ 13.2 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 16-CDIP（0.300"，7.62mm） |
| 供应商设备封装： | 16-CDIP |
| 包装： | 管件 |
AD684
REV. A
–7–
The AD684 does not provide separate analog and digital ground
leads as is the case with most A-to-D converters. The common
pin is the single ground terminal for the device. It is the refer-
ence point for the sampled input voltage and the held output
voltage and also the digital ground return path. The common
pin should be connected to the reference (analog) ground of the
A-to-D converter with a separate ground lead. Since the analog
and digital grounds in the 684 are connected internally, the
common pin should also be connected to the digital ground,
which is usually tied to analog common at the A-to-D converter.
Figure 4 illustrates the recommended decoupling and grounding
practice.
NOISE CHARACTERISTICS
Designers of data conversion circuits must also consider the
effect of noise sources on the accuracy for the data acquisition
system. A sample-and-hold amplifier that precedes the A-to-D
converter introduces some noise and represents another source
of uncertainty in the conversion process. The noise from the
AD684 is specified as the total output noise, which includes
both the sampled wideband noise of the SHA in addition to the
band limited output noise. The total output noise is the rms
sum of the sampled dc uncertainty and the hold mode noise. A
plot of the total output noise vs. the equivalent input bandwidth
of the converter being used is given in Figure 5.
Figure 5. RMS Noise vs. Input Bandwidth of ADC
DRIVING THE ANALOG INPUTS
For best performance, it is important to drive the AD684 analog
inputs from a low impedance signal source. This enhances the
sampling accuracy by minimizing the analog and digital
crosstalk. Signals which come from higher impedance sources
(e.g., over 5k ohms) will have a relatively higher level of
crosstalk. For applications where signals have high source
impedance, an operational amplifier buffer in front of the
AD684 is required. The AD713 (precision quad BiFET op
amp) is recommended for these applications.
HIGH FREQUENCY SAMPLING
Aperture jitter and distortion are the primary factors which limit
frequency domain performance of a sample-and-hold amplifier.
Aperture jitter modulates the phase of the hold command and
produces an effective noise on the sampled analog input. The
magnitude of the jitter induced noise is directly related to the
frequency of the input signal.
A graph showing the magnitude of the jitter induced error vs.
frequency of the input signal is given in Figure 6.
The accuracy in sampling high frequency signals is also con-
strained by the distortion and noise created by the sample-and-
hold. The level of distortion increases with frequency and
reduces the “effective number of bits” of the conversion.
Measurements of Figures 7 and 8 were made using a 14-bit
A-to-D converter with VIN = 10 V p-p and a sample frequency
of 100 kSPS.
Figure 6. Error Magnitude vs. Frequency
Figure 7. Total Harmonic Distortion vs. Frequency
Figure 8. Signal/(Noise and Distortion) vs. Frequency
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相关代理商/技术参数 |
参数描述 |
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| AD684JQ | 功能描述:IC AMP SAMPLE HOLD QUAD 16CDIP RoHS:否 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:1 系列:- 放大器类型:通用 电路数:4 输出类型:满摆幅 转换速率:0.028 V/µs 增益带宽积:105kHz -3db带宽:- 电流 - 输入偏压:3nA 电压 - 输入偏移:100µV 电流 - 电源:3.3µA 电流 - 输出 / 通道:12mA 电压 - 电源，单路/双路(±):2.7 V ~ 12 V，±1.35 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:14-TSSOP 包装:剪切带 (CT) 其它名称:OP481GRUZ-REELCT |
| AD684SQ | 功能描述:IC AMP SAMPLE HOLD QUAD 16CDIP RoHS:否 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:1 系列:- 放大器类型:通用 电路数:4 输出类型:满摆幅 转换速率:0.028 V/µs 增益带宽积:105kHz -3db带宽:- 电流 - 输入偏压:3nA 电压 - 输入偏移:100µV 电流 - 电源:3.3µA 电流 - 输出 / 通道:12mA 电压 - 电源，单路/双路(±):2.7 V ~ 12 V，±1.35 V ~ 6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-TSSOP（0.173"，4.40mm 宽） 供应商设备封装:14-TSSOP 包装:剪切带 (CT) 其它名称:OP481GRUZ-REELCT |
| AD684SQ/883B | 功能描述:采样&保持放大器 IC MONO QUAD SAMPLE/HOLD RoHS:否 制造商:Texas Instruments 通道数量:2 捕获时间:20 us 电源电压-最大:18 V 最大工作温度:+ 85 C 最小工作温度:- 25 C 安装风格: 封装 / 箱体:SOIC-14 封装:Tube |
| AD6871AR | 制造商:Analog Devices 功能描述: |
| AD688 | 制造商:AD 制造商全称:Analog Devices 功能描述:High Precision +-10 V Reference |
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