参数资料
| 型号： | AD9200ARS |
| 厂商： | Analog Devices Inc |
| 文件页数： | 6/24页 |
| 文件大小： | 0K |
| 描述： | IC ADC CMOS 10BIT 20MSPS 28-SSOP |
| 标准包装： | 47 |
| 位数： | 10 |
| 采样率（每秒）： | 20M |
| 数据接口： | 并联 |
| 转换器数目： | 1 |
| 功率耗散（最大）： | 100mW |
| 电压电源： | 单电源 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SSOP（0.209"，5.30mm 宽） |
| 供应商设备封装： | 28-SSOP |
| 包装： | 管件 |
| 输入数目和类型： | 1 个单端，单极 |
AD9200
–14–
REV. E
DRIVING THE ANALOG INPUT
Figure 25 shows the equivalent analog input of the AD9200, a
sample-and-hold amplifier (switched capacitor input SHA).
Bringing CLK to a logic low level closes Switches 1 and 2 and
opens Switch 3. The input source connected to AIN must
charge capacitor CH during this time. When CLK transitions
from logic “low” to logic “high,” Switches 1 and 2 open, placing
the SHA in hold mode. Switch 3 then closes, forcing the output
of the op amp to equal the voltage stored on CH. When CLK
transitions from logic “high” to logic “low,” Switch 3 opens
first. Switches 1 and 2 close, placing the SHA in track mode.
The structure of the input SHA places certain requirements on
the input drive source. The combination of the pin capacitance,
CP, and the hold capacitance, CH, is typically less than 5 pF.
The input source must be able to charge or discharge this ca-
pacitance to 10-bit accuracy in one half of a clock cycle. When
the SHA goes into track mode, the input source must charge or
discharge capacitor CH from the voltage already stored on CH
to the new voltage. In the worst case, a full-scale voltage step on
the input, the input source must provide the charging current
through the RON (50
) of Switch 1 and quickly (within 1/2 CLK
period) settle. This situation corresponds to driving a low input
impedance. On the other hand, when the source voltage equals
the value previously stored on CH, the hold capacitor requires
no input current and the equivalent input impedance is ex-
tremely high.
Adding series resistance between the output of the source and
the AIN pin reduces the drive requirements placed on the
source. Figure 26 shows this configuration. The bandwidth of
the particular application limits the size of this resistor. To
maintain the performance outlined in the data sheet specifica-
tions, the resistor should be limited to 20
or less. For applica-
tions with signal bandwidths less than 10 MHz, the user may
proportionally increase the size of the series resistor. Alterna-
tively, adding a shunt capacitance between the AIN pin and
analog ground can lower the ac load impedance. The value of
this capacitance will depend on the source resistance and the
required signal bandwidth.
The input span of the AD9200 is a function of the reference
voltages. For more information regarding the input range, see
the Internal and External Reference sections of the data sheet.
CH
CP
S1
S3
S2
AIN
(REFTS
REFBS)
SHA
AD9200
Figure 25. AD9200 Equivalent Input Structure
AIN
VS
< 20
AD9200
Figure 26. Simple AD9200 Drive Configuration
In many cases, particularly in single-supply operation, ac cou-
pling offers a convenient way of biasing the analog input signal
at the proper signal range. Figure 25 shows a typical configura-
tion for ac-coupling the analog input signal to the AD9200.
Maintaining the specifications outlined in the data sheet
requires careful selection of the component values. The most
important is the f–3 dB high-pass corner frequency. It is a function of
R2 and the parallel combination of C1 and C2. The f–3 dB point
can be approximated by the equation:
f–3 dB = 1/(2
× pi × [R2] C
EQ)
where CEQ is the parallel combination of C1 and C2. Note that
C1 is typically a large electrolytic or tantalum capacitor that
becomes inductive at high frequencies. Adding a small ceramic
or polystyrene capacitor (on the order of 0.01
F) that does not
become inductive until negligibly higher frequencies, maintains
a low impedance over a wide frequency range.
NOTE: AC coupled input signals may also be shifted to a desired
level with the AD9200’s internal clamp. See Clamp Operation.
AIN
R1
AD9200
IB
R2
VBIAS
C1
C2
VIN
Figure 27. AC Coupled Input
There are additional considerations when choosing the resistor
values. The ac-coupling capacitors integrate the switching tran-
sients present at the input of the AD9200 and cause a net dc
bias current, IB, to flow into the input. The magnitude of the
bias current increases as the signal magnitude deviates from
V midscale and the clock frequency increases; i.e., minimum
bias current flow when AIN = V midscale. This bias current
will result in an offset error of (R1 + R2)
× I
B. If it is necessary
to compensate this error, consider making R2 negligibly small or
modifying VBIAS to account for the resultant offset.
In systems that must use dc coupling, use an op amp to level-
shift a ground-referenced signal to comply with the input re-
quirements of the AD9200. Figure 28 shows an AD8041 config-
ured in noninverting mode.
AIN
20
AD9200
6
7
2
3
4
NC
0.1 F
+VCC
NC
MIDSCALE
OFFSET
VOLTAGE
0VDC
1V p-p
AD8041
5
1
Figure 28. Bipolar Level Shift
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| AD9200ARSRL | 功能描述:IC ADC 10BIT CMOS 20MSPS 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:2,500 系列:- 位数:16 采样率（每秒）:15 数据接口:MICROWIRE?，串行，SPI? 转换器数目:1 功率耗散（最大）:480µW 电压电源:单电源 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:38-WFQFN 裸露焊盘 供应商设备封装:38-QFN（5x7） 包装:带卷 (TR) 输入数目和类型:16 个单端，双极；8 个差分，双极 配用:DC1011A-C-ND - BOARD DELTA SIGMA ADC LTC2494 |
| AD9200ARSZ | 功能描述:IC ADC 10BIT CMOS 20MSPS 28-SSOP RoHS:是 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:microPOWER™ 位数:8 采样率（每秒）:1M 数据接口:串行，SPI? 转换器数目:1 功率耗散（最大）:- 电压电源:模拟和数字 工作温度:-40°C ~ 125°C 安装类型:表面贴装 封装/外壳:24-VFQFN 裸露焊盘 供应商设备封装:24-VQFN 裸露焊盘（4x4） 包装:Digi-Reel® 输入数目和类型:8 个单端，单极 产品目录页面:892 (CN2011-ZH PDF) 其它名称:296-25851-6 |
| AD9200ARSZRL | 功能描述:IC ADC 10BIT CMOS 20MSPS 28-SSOP RoHS:是 类别:集成电路 (IC) >> 数据采集 - 模数转换器 系列:- 标准包装:2,500 系列:- 位数:16 采样率（每秒）:15 数据接口:MICROWIRE?，串行，SPI? 转换器数目:1 功率耗散（最大）:480µW 电压电源:单电源 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:38-WFQFN 裸露焊盘 供应商设备封装:38-QFN（5x7） 包装:带卷 (TR) 输入数目和类型:16 个单端，双极；8 个差分，双极 配用:DC1011A-C-ND - BOARD DELTA SIGMA ADC LTC2494 |
| AD9200JRS | 制造商:Analog Devices 功能描述:ADC Single Pipelined 20Msps 10-bit Parallel 28-Pin SSOP 制造商:Analog Devices 功能描述:ADC SGL PIPELINED 20MSPS 10-BIT PARALLEL 28SSOP - Rail/Tube 制造商:Rochester Electronics LLC 功能描述:10-BIT 20 MSPS, 80 MW CMOS A/D CONVERTER - Bulk 制造商:Analog Devices 功能描述:SEMICONDUCTOR ((NW)) |
| AD9200JRSRL | 制造商:Analog Devices 功能描述:ADC Single Pipelined 20Msps 10-bit Parallel 28-Pin SSOP T/R |
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