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参数资料
| 型号： | AD9225 |
| 厂商： | Analog Devices, Inc. |
| 英文描述： | Complete 12-Bit, 25 MSPS Monolithic A/D Converter |
| 中文描述： | 完整的12位，25 MSPS的单片机的A / D转换器 |
| 文件页数： | 15/24页 |
| 文件大小： | 321K |
| 代理商： | AD9225 |
AD9225
–15–
REV. A
Figure 24 shows the schematic of the suggested transformer
circuit. The circuit uses a minicircuits RF transformer, model
#T4-1T, which has an impedance ratio of four (turns ratio of
2). The schematic assumes that the signal source has a 50
source impedance. The 1:4 impedance ratio requires the 200
secondary termination for optimum power transfer and VSWR.
The center tap of the transformer provides a convenient means
of level-shifting the input signal to a desired common-mode
voltage.
VINA
VINB
AD9225
200
V
49.9
V
R
S
33
V
CML
MINICIRCUITS
T4-1T
0.1
m
F
R
S
33
V
Figure 24. Transformer Coupled Input
This (Figure 24) configuration was used to gather the differen-
tial data on pages 2 and 3.
Transformers with other turns ratios may also be selected to
optimize the performance of a given application. For example, a
given input signal source or amplifier may realize an improve-
ment in distortion performance at reduced output power levels
and signal swings. For example, selecting a transformer with a
higher impedance ratio (e.g., Minicircuits T16-6T with a 1:16
impedance ratio) effectively “steps up” the signal level thus
further reducing the driving requirements of the signal source.
Referring to Figure 24, a series resistors, R
S
, and shunt capaci-
tor, C
S
, were inserted between the AD9225 and the secondary
of the transformer. The value of 33
was selected to specifi-
cally optimize both the THD and SNR performance of the A/D.
R
S
and C
S
help provide a low-pass filter to block high frequency
noise.
The AD9225 can be easily configured for either a 2 V p-p input
span or 4.0 V p-p input span by setting the internal reference
(see Table II). Other input spans can be realized with two exter-
nal gain setting resistors as shown in Figure 28 of this data
sheet. Figures 25a and 25b demonstrate how both spans of the
AD9225 achieve the high degree of linearity and SFDR over a
wide range of amplitudes required by the most demanding com-
munication applications.
Figures 25a and 25b demonstrate the flexibility of common-
mode voltage (transformer center tap) with respect to THD.
COMMON-MODE VOLTAGE – V
–76
–78
–86
–80
–82
–84
0
5
1
T
2
3
4
F
IN
= 10MHz
F
IN
= 2.5MHz
Figure 25a. Common-Mode Voltage vs. THD
(A
IN
= 2 V Differential)
COMMON-MODE VOLTAGE – V
–76
–78
–86
–80
–82
–84
0.5
1.0
T
1.5
F
IN
= 10MHz
F
IN
= 2.5MHz
2.0
2.5
3.0
3.5
4.0
4.5
Figure 25b. Common-Mode Voltage vs. THD
(A
IN
= 4 V Differential)
FUND
2ND
3RD
4TH
–119.7
–110.0
–100.0
–90.0
–80.0
–70.0
–60.0
–50.0
–40.0
–30.0
–20.0
–10.0
0.0
2.0E+6
4.0E+6
6.0E+6
8.0E+6
10.0E+6
12.5E+6
F
IN
= 2.5MHz
F
S
= 25MHz
Figure 25c. Single Tone Frequency Domain Plot
Common-Mode Voltage = 2.5 V (A
IN
= 4 V
Differential)
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相关代理商/技术参数 |
参数描述 |
|---|---|
| AD9225_03 | 制造商:AD 制造商全称:Analog Devices 功能描述:Complete 12-Bit, 25 MSPS Monolithic A/D Converter |
| AD9225AR | 功能描述:IC ADC 12BIT 25MSPS 28-SOIC RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
| AD9225ARRL | 制造商:Analog Devices 功能描述:ADC Single Pipelined 25Msps 12-bit Parallel 28-Pin SOIC W T/R |
| AD9225ARS | 功能描述:IC ADC 12BIT 25MSPS 28-SSOP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1 系列:- 位数:14 采样率（每秒）:83k 数据接口:串行，并联 转换器数目:1 功率耗散（最大）:95mW 电压电源:双 ± 工作温度:0°C ~ 70°C 安装类型:通孔 封装/外壳:28-DIP（0.600"，15.24mm） 供应商设备封装:28-PDIP 包装:管件 输入数目和类型:1 个单端，双极 |
| AD9225ARSRL | 功能描述:IC ADC 12BIT 25MSPS 28-SSOP RoHS:否 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:1,000 系列:- 位数:12 采样率（每秒）:300k 数据接口:并联 转换器数目:1 功率耗散（最大）:75mW 电压电源:单电源 工作温度:0°C ~ 70°C 安装类型:表面贴装 封装/外壳:24-SOIC（0.295"，7.50mm 宽） 供应商设备封装:24-SOIC 包装:带卷 (TR) 输入数目和类型:1 个单端，单极；1 个单端，双极 |
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