参数资料
| 型号： | AD8476ARMZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 13/24页 |
| 文件大小： | 0K |
| 描述： | IC AMP DIFF & ADC DRIVER 8MSOP |
| 标准包装： | 50 |
| 放大器类型： | 差分 |
| 电路数： | 1 |
| 输出类型： | 差分，满摆幅 |
| 转换速率： | 10 V/µs |
| -3db带宽： | 5MHz |
| 电流 - 电源： | 330µA |
| 电流 - 输出 / 通道： | 35mA |
| 电压 - 电源，单路/双路(±)： | 3 V ~ 18 V，±1.5 V ~ 9 V |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 供应商设备封装： | 8-MSOP |
| 包装： | 管件 |
AD8476
Data Sheet
Rev. B | Page 20 of 24
LOW POWER ADC DRIVING
The AD8476 is designed to be a low power driver for ADCs
with up to 16-bit precision and sampling rates of up to
250 kSPS. The circuit in Figure 56 shows the AD8476 driving
the AD7687, a 16-bit, 250 kSPS fully differential SAR ADC.
The filter between the AD8476 and the ADC reduces high
frequency noise and reduces switching transients from the
sampling of the ADC.
Choose the values of this filter with care. Optimal values for the
filter may need to be determined empirically, but the guidelines
discussed herein are provided to help the user. For optimum
performance, this filter should be fast enough to settle full-scale
to 0.5 LSB of the ADC within the acquisition time specified in
the ADC data sheet, in this case, the AD7687. If the filter is
slower than the acquisition time, distortion can result that looks
like harmonics. If the filter is too fast, the noise bandwidth of
the amplifier increases, thereby reducing the SNR of your
system.
Additional considerations help determine the values of the
individual components. THD of the ADC is likely to increase
with source resistance. This is stated in the ADC data sheet.
To reduce this effect, try to use smaller resistance and larger
capacitance. Large capacitance values much greater than 2 nF
are hard for the amplifier to drive. Higher capacitance also
increases the effect of changes in output impedance.
It is also important to consider the signal frequency range of
interest. The AD8476 THD decreases with higher frequency
(see Figure 42) and output impedance increases with higher
frequency (see Figure 49). This higher output impedance yields
slower settling, thus be certain to choose your capacitance so
that the filter still meets the settling requirement at the
maximum frequency of interest.
In the application shown, a 100 Ω resistors and 2.2 nF
capacitors at each output were chosen. For driving the AD7687,
this combination yields an SNR loss of 2.5 dB and good THD
performance for a 20 kHz fundamental frequency, with an ADC
throughput rate of 250kSPS. The filter bandwidth can be
determined by the following equation:
RC
Frequency
Filter
2
1
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
–120
–130
–140
–180
–170
–160
–150
0
20406080
100
120
140
ADC
F
U
L
S
C
AL
E
(
d
B)
FREQUENCY (kHz)
1
019
5-
064
VIN = 8V p-p
THD = –112dB
SNR = 93dB
Figure 55. FFT of AD8476 Driving the AD7687
10
19
5-
06
3
AD8476
AD7687
–OUT
+OUT
+IN
–IN
VOCM
–VS
+VS
+5V
VDD
IN–
IN+
+2.5V
+1.8V TO +5V
+5V
REF
GND
VIO
SDI
SCK
SDO
CNV
100
2.2nF
+4.5V
+2.5V
+0.5V
4V
+4V
+2V
0V
4V
+4V
+2V
0V
4V
+4.5V
+2.5V
+0.5V
4V
Figure 56. AD8476 Conditioning and Level Shifting a Differential Voltage to Drive Single-Supply ADC
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| AD8476ARMZ-R7 | 功能描述:IC AMP DIFF ADC DVR 8MSOP RoHS:是 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:0.6 V/µs 增益带宽积:1MHz -3db带宽:- 电流 - 输入偏压:2pA 电压 - 输入偏移:1000µV 电流 - 电源:85µA 电流 - 输出 / 通道:20mA 电压 - 电源，单路/双路(±):1.8 V ~ 6 V 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:14-SOIC（0.154"，3.90mm 宽） 供应商设备封装:14-SOICN 包装:剪切带 (CT) 产品目录页面:680 (CN2011-ZH PDF) 其它名称:MCP6L04T-E/SLCT |
| AD8476ARMZ-RL | 功能描述:IC AMP DIFF ADC DVR 8MSOP RoHS:是 类别:集成电路 (IC) >> Linear - Amplifiers - Instrumentation 系列:- 标准包装:50 系列:LinCMOS™ 放大器类型:通用 电路数:4 输出类型:- 转换速率:0.05 V/µs 增益带宽积:110kHz -3db带宽:- 电流 - 输入偏压:0.7pA 电压 - 输入偏移:210µV 电流 - 电源:57µA 电流 - 输出 / 通道:30mA 电压 - 电源，单路/双路(±):3 V ~ 16 V，±1.5 V ~ 8 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:14-SOIC（0.154"，3.90mm 宽） 供应商设备封装:14-SOIC 包装:管件 产品目录页面:865 (CN2011-ZH PDF) 其它名称:296-1834296-1834-5 |
| AD8476BCPZ-R7 | 功能描述:IC AMP DIFF ADC DVR 16LFCSP RoHS:是 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 |
| AD8476BCPZ-RL | 功能描述:IC AMP DIFF ADC DVR 16LFCSP RoHS:是 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 |
| AD8476BCPZ-WP | 功能描述:差分放大器 Low Power Unity Gain & ADC Driver RoHS:否 制造商:Analog Devices 通道数量:1 Channel 带宽:900 MHz 可用增益调整:5.6 dB to 20 dB 输入补偿电压:1 mV at 5 V 共模抑制比（最小值）:67 dB 工作电源电压:11 V 电源电流:28 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 安装风格:SMD/SMT 封装 / 箱体:SOIC-8 封装:Reel |
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