参数资料
| 型号： | AD781JNZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 7/8页 |
| 文件大小： | 0K |
| 描述： | IC AMP SAMPLE HOLD LP 5MA 8DIP |
| 标准包装： | 50 |
| 放大器类型： | 采样和保持 |
| 电路数： | 1 |
| -3db带宽： | 4MHz |
| 电流 - 输入偏压： | 50nA |
| 电流 - 电源： | 4mA |
| 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： | 0°C ~ 70°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 8-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 8-PDIP |
| 包装： | 管件 |
| 产品目录页面： | 766 (CN2011-ZH PDF) |
AD781
REV. A
–7–
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 of 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
AD781 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.
300
0
1k
10M
200
100
10k
1M
100k
FREQUENCY – Hz
OUTPUT
NOISE
–
V
rms
Figure 5. RMS Noise vs. Input Bandwidth of ADC
DRIVING THE ANALOG INPUTS
For best performance, it is important to drive the AD781 analog
input 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 5 k
) will have a relatively higher level of crosstalk.
For applications where signals have high source impedance, an
operational amplifier buffer in front of the AD781 is required.
The AD711 (precision 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 re-
duces the “effective number of bits” of the conversion.
Measurements of Figures 7 and 8 were made using a 14-bit A/D
converter with VIN = 10 V p-p and a sample frequency of
100 kSPS.
1%
1k
1M
0.1%
0.01%
10k
100k
FREQUENCY – Hz
APERTURE JITTER TYPICAL AT 50ps
1/2 BIT @
8 BITS
1/2 BIT @
10 BITS
1/2 BIT @
12 BITS
1/2 BIT @
14 BITS
Figure 6. Error Magnitude vs. Frequency
–65
–95
1M
–80
–90
1k
–85
100
–70
–75
100k
10k
FREQUENCY – Hz
THD
–
dB
Figure 7. Total Harmonic Distortion vs. Frequency
90
0
100k
20
10
1k
100
30
40
50
60
70
80
10k
FREQUENCY – Hz
S/(N
+
D)
–
dB
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 |
|---|---|
| AD781SQ | 制造商:AD 制造商全称:Analog Devices 功能描述:Complete 700 ns Sample-and-Hold Amplifier |
| AD7820 | 制造商:AD 制造商全称:Analog Devices 功能描述:LC2MOS HIGH-SPEED uP-COMPATIBLE 8-BIT ADC WITH TRACK/HOLD FUNCTION |
| AD7820BCHIPS | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog-to-Digital Converter， 8-Bit |
| AD7820BQ | 功能描述:IC ADC 8BIT HS TRACK/HOLD 20CDIP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 位数:12 采样率（每秒）:3M 数据接口:- 转换器数目:- 功率耗散（最大）:- 电压电源:- 工作温度:- 安装类型:表面贴装 封装/外壳:SOT-23-6 供应商设备封装:SOT-23-6 包装:带卷 (TR) 输入数目和类型:- |
| AD7820CQ | 功能描述:IC ADC 8BIT HS TRACK/HOLD 20CDIP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 其它有关文件:TSA1204 View All Specifications 标准包装:1 系列:- 位数:12 采样率（每秒）:20M 数据接口:并联 转换器数目:2 功率耗散（最大）:155mW 电压电源:模拟和数字 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-TQFP 供应商设备封装:48-TQFP（7x7） 包装:Digi-Reel® 输入数目和类型:4 个单端，单极；2 个差分，单极 产品目录页面:1156 (CN2011-ZH PDF) 其它名称:497-5435-6 |
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