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参数资料
| 型号： | AD7942 |
| 厂商： | Analog Devices, Inc. |
| 元件分类： | ADC |
| 英文描述： | 14-Bit, 250 kSPS PulSAR ADC in MSOP/QFN |
| 中文描述： | 14位，250 kSPS的PulSAR系列ADC的，采用MSOP / QFN封装 |
| 文件页数： | 8/28页 |
| 文件大小： | 633K |
| 代理商： | AD7942 |
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AD7942
Preliminary Technical Data
Rev Pr B | Page 16 of 28
Driver Amplifier Choice
Although the AD7942 is easy to drive, the driver amplifier
needs to meet the following requirements:
The noise generated by the driver amplifier needs to be
kept as low as possible in order to preserve the SNR and
transition noise performance of the AD7942. Note that the
AD7942 has a noise much lower than most of the other 14-
bit ADCs and, therefore, can be driven by a noisier op amp
while preserving the same or better system performance.
The noise coming from the driver is filtered by the AD7942
analog input circuit 1-pole, low-pass filter made by R1 and
C2 or by the external filter, if one is used.
For ac applications, the driver needs to have a THD
performance suitable to that of the AD7942. Figure 12
gives the THD versus frequency that the driver should
exceed.
For multichannel multiplexed applications, the driver
amplifier and the AD7942 analog input circuit must be able
to settle for a full-scale step of the capacitor array at a 14-
bit level (0.006%). In the amplifier’s data sheet, settling at
0.1% to 0.01% is more commonly specified. This could
differ significantly from the settling time at a 14-bit level
and should be verified prior to driver selection.
Table 9. Recommended Driver Amplifiers.
Amplifier
Typical Application
Very low noise and high frequency
Low noise and high frequency
Low power, low noise, and low frequency
5 V single-supply, low power
Small, low power and low frequency
High frequency and low power
Voltage Reference Input
The AD7942 voltage reference input, REF, has a dynamic input
impedance and should therefore be driven by a low impedance
source with efficient decoupling between the REF and GND
pins as explained in the Layout section.
When REF is driven by a very low impedance source, e.g., a
(X5R, 0805 size) ceramic chip capacitor is appropriate for
optimum performance.
If an unbuffered reference voltage is used, the decoupling value
depends on the reference used. For instance, a 22 F (X5R, 1206
size) ceramic chip capacitor is appropriate for optimum
performance using a low temperature drift ADR43x reference.
If desired, smaller reference decoupling capacitor values down
to 2.2 F can be used with a minimal impact on performance,
especially DNL.
相关PDF资料 |
PDF描述 |
|---|---|
| AD7943BN | +3.3 V/+5 V Multiplying 12-Bit DACs |
| AD7943BR | +3.3 V/+5 V Multiplying 12-Bit DACs |
| AD7943BRS | +3.3 V/+5 V Multiplying 12-Bit DACs |
| AD7945BN | +3.3 V/+5 V Multiplying 12-Bit DACs |
| AD7945BR | +3.3 V/+5 V Multiplying 12-Bit DACs |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD79421 | 制造商:AD 制造商全称:Analog Devices 功能描述:18-Bit, 2 MSPS PulSAR 15 mW ADC in LFCSP (QFN) |
| AD7942BCPRL7 | 制造商:AD 制造商全称:Analog Devices 功能描述:14-Bit, 250 kSPS PulSAR ADC in MSOP/QFN |
| AD7942BCPWP | 制造商:AD 制造商全称:Analog Devices 功能描述:14-Bit, 250 kSPS PulSAR ADC in MSOP/QFN |
| AD7942BCPZRL | 功能描述:IC ADC 14BIT SAR 250KSPS 10LFCSP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:PulSAR® 标准包装:1,000 系列:- 位数:16 采样率（每秒）:45k 数据接口:串行 转换器数目:2 功率耗散（最大）:315mW 电压电源:模拟和数字 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:28-SOIC（0.295"，7.50mm 宽） 供应商设备封装:28-SOIC W 包装:带卷 (TR) 输入数目和类型:2 个单端，单极 |
| AD7942BCPZRL1 | 制造商:AD 制造商全称:Analog Devices 功能描述:14-Bit, 250 kSPS PulSAR, Pseudo Differential ADC in MSOP/QFN |
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