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参数资料
| 型号： | AD9051 |
| 厂商： | Analog Devices, Inc. |
| 英文描述： | 10-Bit, 60 MSPS A/D Converter |
| 中文描述： | 10位，60 MSPS的A / D转换 |
| 文件页数： | 10/12页 |
| 文件大小： | 142K |
| 代理商： | AD9051 |
AD9051
–10–
REV. A
Overdrive of the Analog Input
Special care was taken in the design of the analog input section
of the AD9051 to prevent damage and corruption of data when
the input is overdriven. The nominal input range is +1.875 V
to 3.125 V (1.25 V p-p centered at 2.5 V). Out-of-range com-
parators detect when the analog input signal is out of this range
and the input buffer is clamped. The digital outputs are locked
at their maximum or minimum value (i.e., all “0” or all “1”).
This precludes the digital outputs changing to an invalid value
when the analog input is out of range.
The input is protected to one volt outside the power supply
rails. For nominal power (+5 V and ground), the analog input
will not be damaged with signals from +5.5 V to –0.5 V.
Timing
The performance of the AD9051 is very insensitive to the duty
cycle of the clock. Pulsewidth variations of as much as
±
15%
for encode rates of 40 MSPS and
±
10% for encode rates of
60 MSPS will cause no degradation in performance. (See Fig-
ure 17, SNR vs. Duty Cycle.)
The AD9051 provides latched data outputs, with five pipeline
delays. Data outputs are available one propagation delay (t
PD
)
after the rising edge of the encode command (refer to Fig-
ure 1, Timing Diagram). The length of the output data lines
and loads placed on them should be minimized to reduce tran-
sients within the AD9051; these transients can detract from the
converter’s dynamic performance.
Power Dissipation
The power dissipation specification in the parameter table is
measured under the following conditions: encode is 60 MSPS,
analog input is –FS.
As shown in Figure 3, the actual power dissipation varies based
on these conditions. For instance, reducing the clock rate will
reduce power as expected for CMOS-type devices. The loading
determines the power dissipated in the output stages.
The analog input frequency and amplitude in conjunction with
the clock rate determine the switching rate of the output data
bits. Power dissipation increases as more data bits switch at
faster rates. For instance, if the input is a dc signal that is out of
range, no output bits will switch. This minimizes power in the
output stages, but is not realistic from a usage standpoint.
The dissipation in the output stages can be minimized by inter-
facing the outputs to 3 V logic (refer to Using the AD9051, 3 V
System). The lower output swings minimize power consump-
tion as follows: (1/2 C
LOAD
×
V
DD2
×
Update Rate).
Voltage Reference
A stable and accurate +2.5 V voltage reference is built into the
AD9051 (Pin 3, VREFOUT). In normal operation the internal
reference is used by strapping together Pins 3 and 4 of the
AD9051. The internal reference has 500
μ
A of extra drive cur-
rent that can be used for other circuits.
Some applications may require greater accuracy, improved
temperature performance, or adjustment of the gain of the
AD9051, which cannot be obtained by using the internal refer-
ence. For these applications, an external +2.5 V reference can
be used to connect to Pin 4 of the AD9051. The VREFIN
requires 2
μ
A of drive current.
The input range can be adjusted by varying the reference volt-
age applied to the AD9051. No appreciable degradation in
performance occurs when the reference is adjusted
±
5%. The
full-scale range of the ADC tracks reference voltage changes
linearly.
EVALUATION BOARD
The AD9051 evaluation board is a convenient and easy way to
evaluate the performance of the AD9051.
Analog Input
The evaluation board requires a 1.25 V p-p input. The signal is
buffered by an AD9631 op amp in the unity gain configuration.
The signal is then ac coupled before entering the AD9051
where a dc offset is internally generated. Leave E3 unconnected
to E4 for usage with the AD9631. To evaluate performance
without this buffer, remove the AD9631 and connect E3 to E4.
Keep E1 connected to E2 for use in the low bandwidth mode
(50 MHz). Removing this connector will enable high band-
width mode (130 MHz). Low bandwidth is the recommended
mode of operation in order to minimize any high frequency
noise coupling into the input of the AD9051.
Encode
The evaluation board is driven with a TTL or CMOS clock
into a clock buffer of ac type CMOS logic. This buffer will
drive the encode to the AD9051, the data latches, and a “data
ready.”
Data Out
The digital data is captured by a pair 74ACQ574 latches. Any
unused connector pins should be grounded to the device that is
capturing data from the evaluation board. This minimizes any
grounding loops that may degrade performance. A separate
power plane is provided for supplying the latches, clock buffer,
and digital outputs of the AD9051. This supply can be 3 V or
5 V.
Layout
The AD9051 is not layout sensitive if some important guide-
lines are met. The evaluation board layout provides an ex-
ample where these guidelines have been followed to optimize
performance.
Provide a solid ground plane connecting both analog and
digital sections. Cuts in this plane near the AD9051 should
be kept to a minimum.
Excellent bypassing is essential. All capacitors should be
placed as close as possible to the AD9051. No vias should
be used to connect capacitors to the AD9051 as this may
create a parasitic inductance that can reduce bypassing
effectiveness.
The AD9051 evaluation board is provided as a design example
for customers of Analog Devices. ADI makes no warranties
express, statutory, or implied regarding merchantability of
fitness for a particular purpose.
相关PDF资料 |
PDF描述 |
|---|---|
| AD9051-2V | 10-Bit, 60 MSPS A/D Converter |
| AD9051-2VPCB | 10-Bit, 60 MSPS A/D Converter |
| AD9051BRS | 10-Bit, 60 MSPS A/D Converter |
| AD9051BRS-2V | 10-Bit, 60 MSPS A/D Converter |
| AD9051PCB | 10-Bit, 60 MSPS A/D Converter |
相关代理商/技术参数 |
参数描述 |
|---|---|
| AD9051/PCB | 制造商:Analog Devices 功能描述:10-BIT 60 MSPS ADC - Bulk |
| AD9051-2V | 制造商:AD 制造商全称:Analog Devices 功能描述:10-Bit, 60 MSPS A/D Converter |
| AD9051-2V/PCB | 制造商:Analog Devices 功能描述:Development Tools, Evaluation Board for AD9051-2V 制造商:Analog Devices 功能描述:10-BIT 60 MSPS ADC - Bulk |
| AD9051-2VPCB | 制造商:AD 制造商全称:Analog Devices 功能描述:10-Bit, 60 MSPS A/D Converter |
| AD9051BRS | 功能描述:IC ADC 10BIT 60MSPS 28-SSOP 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:- |
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