| 主题：如何正确选择数模转换器 |
| 在线问答 |
| [问：wangda
weidavid] |
请问专家，如果所做系统要求数模转换的精度很高，而速度没有什么要求，那应选择哪种芯片比较合算，就是说可以达到要求，又比较省钱。谢谢 |
| [答：Mariah] |
For high resolution and low speed DAC, you can consider sigma-delta
DACs. This kind of DACs are also cheap. |
[2003-10-30 10:47:58] |
| [问：hjldfp] |
如何选择14位50MHz的A/D D/A芯片 |
| [答：William] |
In general, the A/D, D/A selection is dependent on the type of end
application you are working on. For example, for communication,
SFDR is important. Please refer to the product datasheet and
selection guide for details. |
[2003-10-30 10:52:03] |
| [问：qiangnet] |
能否简单介绍下目前D/A 转换器的工艺发展？失效模式？ |
| [答：Albert] |
Failure modes related to DACs generally result from mis application of
the device.Usually overvoltage, breaking the absolute max ratings
etc |
[2003-10-30 10:52:59] |
| [问：davidlu] |
应用于视频（1Vpp，PAL625--1249，NTSC525--1024）采集，10位或12位并行输出，如何选用数模转换器？谢谢。 |
| [答：Wayne] |
I think you mean video decoder, not DAC. So, you can choose ADV7189,
which support 10/20bit extended standard. However, if you just want to
convert directly the CVBS signal to digital data, then you can use AD9203
which is 10bit 40MSPS ADC, or AD9200 which is 10bit and 20MSPS, AD9051
10bit 60MSPS. |
[2003-10-30 10:53:17] |
| [问：aini8833
456.student] |
数模转换器种类和特性是怎样划分的？还有就是怎样和计算机相连？ |
| [答：Mariah] |
The classification of DACs is according several criterions, such as
speed, I/O types etc.You can use the UART protocol of your MCU to
communicate with PC. |
[2003-10-30 10:53:59] |
| [问：samire] |
DAC的输出如何和平滑滤波器连接?对滤波器有何要求?如何进行设计这种滤波器? |
| [答：Mariah] |
You can find the filter design reference tools by the link below.
http://www.analog.com/techSupport/designTools
/interactiveTools/filter/filter.html |
[2003-10-30 10:59:25] |
| [问：john_ren] |
1.选择转换器时，应当重点注意那些问题？在基本参数符合要求，我们一般重点考虑价格，请提供参考意见2.在对转换的数据进行加密时，有那些常用芯片，常用什么算法？3.转换器有无内置放大，即可以直接对模拟信号进行转换? |
| [答：William] |
1) Cost is certainly very important. However, the lowest
system cost doesn"t always mean choosing the lowest cost
component. For example, higher performance product, even though
it means higher component cost, can help reduce manufacturing cost (less
adjustment, shorter development time, etc.)2) The encryption is
usually done at the FPGA/DSP behind the ADC. There are
many algorithm available, depending on how much protection you
need.3) Many ADC"s have PGA built-in. Please refer to the
selection guide. |
[2003-10-30 11:00:05] |
| [问：grey_
yz1949] |
请问，目前最快的DAC芯片速度能达到多少M |
| [答：LiaoWS] |
The fastest DAC ADI can provide now is 500MHz. The part numbers are
AD9782/4/6. |
[2003-10-30 11:00:19] |
| [问：gecheng
liang] |
产品在中国的销售代理和技术支持是哪几家公司？高速处理芯片选型，开发需要哪些配套设备和开发软件？国内有没有用AD高速处理芯片作过开发，能否提供技术支持？购货周期一般是多长时间？ |
| [答：William] |
We have 5 distributors in China. Arrow, Avnet
(Chinatronics), Future, GEHK/Excelpoint, and WPG. There are
many companies who have used our high speed ADC. We have
several experts who specialize in high speed ADC. You can call
our 800-810-1742 for technical support. Typical delivery
timeframe is 4-6 weeks for our products. |
[2003-10-30 11:04:13] |
| [问：vanbingo] |
如何选用数模转换器的精度 |
| [答：Mariah] |
You can find the accuracy specification in the datasheet. The accuracy
selection of the parts is decided by your application. |
[2003-10-30 11:05:44] |
| [问：john_ren] |
1.如何实现转换电路与接口电路的电平兼容，常用那些方法？2.当需要不同的采样率进行采样时，如何实现？3.数字滤波如何工作的？当码流变换时如何适应，FIR滤波器可以解决这个问题吗？ |
| [答：Wayne] |
1. Normally you can use level translation like ADG3245/6/7.2.
Don"t understand your question, could you make it clear, or you can call
8008101742 later for discussion.3. It"s a complicated question,
however you can find a chapter in ADI book "Mixed-Signal and DSP design
techniques". You can find the PDF file on www.analog.com by searching the
words. |
[2003-10-30 11:07:39] |
| [问：662135] |
数模转换器的位数选择很重要吗？ |
| [答：Mariah] |
Yes, it is the first important parameter when you select the part. It
is decided by your application requirement. |
[2003-10-30 11:07:47] |
| [问：guorock] |
SFDR是数字自由杂散动态范围，它是如何定义的？该指标对什么有影响？ |
| [答：LiaoWS] |
You can find its definition from the datasheet of ADI DACs, AD9772 for
example. It will influence the dynamic range of the system. |
[2003-10-30 11:07:51] |
| [问：lichun
lei_1979] |
现在最快的模数/数模转换器采样率是多少？市场价格多少钱？主要用于高速数据采集及重现。谢谢！ |
| [答：William] |
One needs to consider also the resolution when talking about
speed. Also, the speed is highly dependent on the
application. For example, for communication, speed is in the
order of hundreds of MHz. But for instrumentation, the speed is
only at a few MSPS. Price also varies quite a bit from
application to application because of different performance
requirement. |
[2003-10-30 11:08:54] |
| [问：izk] |
如果DAC输入数据是高达200兆的LVDS的逻辑信号，ADI的产品有能满足该需求的解决方案吗？ |
| [答：Wayne] |
We"re designing this kind of DACs, the part# should be AD972x, which
is scheduled to release in 2004. |
[2003-10-30 11:08:56] |
| [问：ShaoJunmei] |
频率很高的情况下,如500M,A/D,D/A的选择,最应该注意是什么方面的问题? |
| [答：Albert] |
at 14 bit resolution, 400Msps ad9775at 16 bit resolution, 400Msps
ad9777AD9723/24/25 will feature 600MSPS and are currently in
definition.All products supported by the analog devices High Speed
Converter Group. |
[2003-10-30 11:09:08] |
| [问：zddpy] |
数据线与CPU控制器总线如何隔离最好。 |
| [答：William] |
Typically, one needs to take care of the isolation of analog and
digital lines with separate grounding and enough physical distance between
the lines. It is also dependent on the frequency of your bus
and the signal. |
[2003-10-30 11:10:50] |
| [问：ZHJNAME] |
请问一下，能不能推荐常用的8，12位的DAC（较高的性价比，电压输出）？ |
| [答：Mariah] |
8bits:AD5300,AD5301,AD533010bits:AD5310,AD5311,AD5331If you
wants to get the product shor form of ADI,you can call toll-free number
800-810-1742 to get it. |
[2003-10-30 11:11:08] |
| [问：SUMMER
_CHEN] |
如何降低DAC的噪声？对于时钟有何特殊要求？ |
| [答：Albert] |
Precision DACs use architecture based around R-2R architectures and
generally do not require a high frequency clock.In high speed
converters the clock is an integral part of the DAC and clock
jitter,overshoot and undershoot on the clock signal contribute to
noise. |
[2003-10-30 11:12:45] |
| [问：wswtiger] |
如何确保高分辨率高速（14bit
40MHz）的ADC的正确设计，在数模转换器的选择中电流输出型和电压输出型的究竟应该怎样选择呢，他们的优点各是什么呢？ |
| [答：Jing] |
You can accord to you design to select the correspond ADCs with
relative INL,DNL and the interface . If you want to get more flexibility
and high speed ,you can select the current output DAC. Of course ,you
should add another amplifier after the current DAC to get the voltage
output in needs. |
[2003-10-30 11:14:43] |
| [问：shijh] |
14.9MHz的DDS应与什么样的D／A最佳匹配？ |
| [答：LiaoWS] |
ADI"s DDS integragtes DAC in it. You can use AD983X series of
DDS. |
[2003-10-30 11:14:48] |
| [问：SUMMER
_CHEN] |
请问，通讯领域中采用的数字中频技术，会用到高速的DA器件，那么ADI在这方面有什么样的产品，有何特点？ |
| [答：Wayne] |
It depends on what kind of communication system you"re doing, SW, or
3G. Basically you can choose TxDAC family like AD9786 (16bit, 400MSPS),
AD977x, high level interpolation, and high sample rate is main feature.
For integrated solution with ADC/DAC together we have MxFE family like
AD986x (dual ADC + Dual DAC, high speed, and with some auxiliary ADC/DAC).
We"ve also DDS AD983x, AD985x for your design. |
[2003-10-30 11:15:31] |
| [问：hdwliang] |
请问如何用DA实现4-20mA输出 |
| [答：LiaoWS] |
ADI has such kind of parts: AD420 and AD421, both 16-bit
accuracy. |
[2003-10-30 11:15:46] |
| [问：tuolang2000] |
现在的MCU中是不是有些已经内置了A/D,D/A转换？？？？ |
| [答：Jing] |
Yes .Our ADuCXXX serial product such as ADuC812,ADuC814,ADuC831/2 and
ADuC841/2 etc is such kind of MCU |
[2003-10-30 11:16:12] |
| [问：ljp] |
DAC用作遥控,和MCU相连时,我该选择串行接口或并行接口?请专家给点建议. |
| [答：Mariah] |
Serial interface is used for small, low power applications.Parallel is
used for fast update low overhead, and high channel count
applications. |
[2003-10-30 11:16:19] |
| [问：kzw] |
有什么型号的DAC，是四通道的，12位并行的，转换速度不低于500K? |
| [答：Jing] |
you can refer to our AD5340/1 |
[2003-10-30 11:16:42] |
| [问：QZDZ] |
现在高速DAC数据输入主要采用什么样的传输模式及通讯协议,对数据传输方面有什么特殊的要求或在设计方面应该特别留意的地方. |
| [答：LiaoWS] |
Now the interface between microcontroller and DAC is mainly TTL/CMOS
level, but later there will be LVDS interface. What you should take care
is the layout, grounding and decoupling. |
[2003-10-30 11:17:25] |
| [问：kzw] |
AD公司的芯片精度比较高，这是大家公认的，但有一点不太好，就是太容易被烧掉了，我想问一下是为什么？难道是精度高就易坏吗？另外，芯片坏了一般不怎么发热，总是烧了还不知道，烧了后并不是不能工作，而是性能变坏，比如说，转换速度变慢。 |
| [答：William] |
I don"t believe our product is more easy to damage. It is,
however, generally true that a "mixed signal" product is more sensitive to
ESD damage (than purely digital or analog). It is simply
because when one combines both analog and digital technologies onto the
same IC, the process becomes less robust to ESD. What you
describes is a bit strange, I"m curious if it was because the product was
purchased from "electronic market" where the quality is often not
stable. |
[2003-10-30 11:17:42] |
| [问：riple] |
如何正确选择数模转换器:转换速率和带宽应如何取舍？ |
| [答：MelConway] |
Conversion speed [settling time] and bandwidth specifications depend
greatly on the DAC architecture.Bandwidth can either be1]
multiplying bandwidth which is the maximum frequency that can be applied
to the Reference input or2] waveform generation bandwidth which is
related to the DAC digital input update rate, which depends on the
interface type, and conversion speed. This bandwidth also depends on the
SFDR Spurious Free Dynamic Range or THD Total Harmonic Distortion which
give a measure of the quality of the output at certain
frequencies.The highest bandwitdth is always obtained from Current
Output DACs which have no input/reference buffers or output buffers to add
delays to the signal processing. Of course parallel interface DACs update
faster and are therefore more suitable for higher
bandwidths.Everything depends on the actual frequencies that are
to be used, and whether the application is processing a signal input or
generating a signal output.Use Voltage output DACs upto approx 100kHz,
and Current output above this.Parallel interface allows an update rate
of upto 50MHz, while Serial interface allows update rate upto approx
3MHz.Example the AD5443 has a multiplying bandwidth of 10MHz+ but an
update rate of only approx 3MHz as it is Serial interface. The AD5445 with
Parallel interface can update upto 50MHz but the settling time limits the
usable bandwidth to approx 10MHz.Please contact our Applications
Engineers with more details of the application for a selection of suitable
parts. |
[2003-10-30 11:18:16] |
| [问：wffae] |
请问，要达到高精度，对 reference voltage
要求一定很高吗？ |
| [答：LiaoWS] |
The voltage reference"s accuracy influence the accuracy of the part.
So for high performance DAC, it needs high performance reference. |
[2003-10-30 11:19:41] |
| [问：yoursdd] |
如果对视频信号进行数模/模数转换该如何选择转换器，它的关键性规格是哪几个方面呢？谢谢！ |
| [答：Wayne] |
If you want to decode CVBS or Y/C signal to YUV digital data, then you
can use video decoder like ADV7189, ADV7183A. And for encoder, you can use
ADV717x (SDTV), ADV719x (some support progressive scan video), ADV73xx
(support HDTV). ADI advantage is high oversample rate, high SNR, noise
figure.If you want to convert RGB from digital to analog RGB, then
ADV7123/7/8 is choices.If you want to convert CVBS directly to digital
data by time, then general purpose ADC like AD9203, AD9200, AD9051 as
10bit resolution. You can also use AD922x as 12bit solution. |
[2003-10-30 11:21:17] |
| [问：qin] |
多通道的DAC的通道匹配性能如何保证? |
| [答：Theresa] |
DAC-to-DAC crosstalk is defined as the glitch impulse that appears at
the output of one DAC output due to both the digital change and subsequent
analog O/P change at another DAC. The victim channel is loaded with
midscaleand DAC-to-DAC crosstalk is specified in nV-s. |
[2003-10-30 11:22:51] |
| [问：wffae] |
请问贵公司的D/A一致性如何？我曾用过台湾多家D/A但产品的一致性差，在同样条件和环境下，输出的摸拟电压值有差异，不得不对每个产品作补偿调整。 |
| [答：William] |
The specifications are guaranteed in the datasheet. You can
refer to the DC performance (such as offset and gain error) for further
details. |
[2003-10-30 11:23:44] |
| [问：qin] |
请介绍电源对高速DAC的噪音影响.是否需要用线性调整器而不用开关电源?如果用开关电源,对它的波纹如何进行处理? |
| [答：LiaoWS] |
For analog circuits, linear power supply is required. But switched
power supply can be used if you can filter it well. If you want to filter
the ripples in the power supply, your weapons are capacitors, inductors.
For more details, send mail to china.support@analog.com, please. |
[2003-10-30 11:23:57] |
| [问：qinqingzi] |
1MSPS的转换率，如果由外部提供时钟，会不会有不稳定之类的问题 |
| [答：Jing] |
General Crystal Oscillator can generate up to 30MHz frequency. You can
use a external clock and be aware to the filter circuit and the stability
of the voltage reference source. |
[2003-10-30 11:24:30] |
| [问：lwbence] |
DAC的一些相关指标在各个领域的应用中有没有一些标准，比如在通信领域的要求或是其它领域 |
| [答：LiaoWS] |
The specifications for the DAC is different from application to
application. For communication systems, the requirement is the SNR, SFDR,
etc. Which are mainly frequency domain specs. |
[2003-10-30 11:25:30] |
| [问：ljp] |
如果8位DAC没有串行口,如何和串口的MCU相连接?是否要加串并转换?对这转换有何要求? |
| [答：Mariah] |
If the MCU has parallel port, you can connect the DAC to MCU directly.
If you just wants to use serial port, you should convert parallel to
serial. You should pay attention to the level consistency of the
conversion. |
[2003-10-30 11:26:58] |
| [问：wwenguang] |
DA的一个参数:MSPS UPDATE
RATE是什么意思,是不是最高的工作频率? |
| [答：LiaoWS] |
MSPS is million samples per secondUpdate rate is MSPS for many
converters,e xcept the Sigma-Delta ones. They are not maximum working
frquency, they are the frequency that converter can work normally. The
maximum should be faster than them. |
[2003-10-30 11:27:01] |
| [问：hua_xing_jiang] |
请推荐几种用于通讯的转换器芯片。谢谢。 |
| [答：LiaoWS] |
In whihc kind of wireless system?For 3G, we have AD6644/5,
AD6623/4, AD6634/6, AD6650/2, AD9777, AD9786 and so on.For
details, contact 800 810 1742, please. |
[2003-10-30 11:28:06] |
| [问：kenvert.lee] |
刚才提到DAC的失效模式，请问，通常有哪些设计上的不当会导致DAC失效？DAC最容易损坏的是哪一部分？谢谢！ |
| [答：Albert] |
Designs that cannot tolerate failure include mission critical
applications, in medical, military etc.Dacs sections prone to failure
include:(a) the power supply pins due to overvoltage from high voltage
spikes on the power supply generated fron inductive switching
in the system etc. (b)Interface lines again due to
overvoltage.(c)Output amplifier due to ESD and overvoltage All
failure modes are generally attributed to mis application of the device.
Generally when the devices are very robust when operated within their
absolute max ratings. |
[2003-10-30 11:28:22] |
| [问：chenpld] |
在视频信号的DAC选择上，为达到广播级的质量，有什么要注意的？谢谢！ |
| [答：Wayne] |
Basically you need to follow broadcasting standards locally. At first,
you need enough oversample rate, then SNR to reach one of the
requirements. ADV719x can be good choice. ADV73xx is new coming family
which has 108MSPS or even 216MSPS sample rate. ADI has some other
properity technology in video, like DNR, SSAF filter, which help to reach
the requirement. |
[2003-10-30 11:29:23] |
| [问：ljp] |
5.
串行DAC的时序控制较麻烦,和微控制器的I/O通信时间较长,除了改用并行DAC,还有什么好办法? |
| [答：LiaoWS] |
For serial interface, few wires will be needed. It is suitable for
multi-channel applications. For high speed DACs, most of them are parallel
interface. |
[2003-10-30 11:29:54] |
| [问：zbchen69] |
如何考虑DNL 和INL
对转换精度的影响问题？在选择相关芯片时应如何考虑？ |
| [答：William] |
DNL and INL represent the linearity of the
conversion. Depending on your application, you need to decide
how much error you can allow in the code from the ideal value. |
[2003-10-30 11:31:04] |
| [问：421956] |
请问：用于直流伺服电机控制的DAC在精度与速度上一般选用什么类型的DAC比较好，是电压输出的，还是电流输出型的！ |
| [答：Albert] |
Again DAC selection is highly dependant on the system and its
requirements which will determine the accuracy and speed of the
DAC.Generally voltage output DACs are a more complete solution. Iout
DACs generally can only supply 2mA max and require an external amplifier
for current to voltage conversion. |
[2003-10-30 11:32:37] |
| [问：wyhljb] |
在数模转换中，中间所经过的途径与通信中的数字信号和摸仪信号是同样的吗？？ 转换中的干扰有那些要注意的？？？ |
| [答：Mariah] |
I am not sure about the "approach" meaning? If you wants to get more
help, please call toll-free number 800-810-1742. |
[2003-10-30 11:32:54] |
| [问：qin] |
如果降低温度对DAC性能的影响?或者提高温度使用范围? |
| [答：William] |
Many DAC"s come with a reference input. The temperature
performance can be usually enhanced by using an external, low tempco
reference to extend the temperature range of the DAC. Note that
all semiconductor products have temperature grade. One should
not use a product beyond the range. |
[2003-10-30 11:33:13] |
| [问：ljp] |
ADI公司有没有ADC和DAC在同一封装里的产品? |
| [答：Wayne] |
For precison solution, Microconvertor series like ADuC81x/2x/3x/4x is
good choice which integrate ADC (12/16/24 bit, 200KSPS....), 8051 MCU and
12bit DACs or PWM output in one chip.For high speed solution, you can
find MxFE family including AD986x, AD987x which has broad applications in
STB, modem, communication systems. |
[2003-10-30 11:33:44] |
| [问：qiangnet] |
能否推荐一个10M/8bit输出的D/A转换器？此外，深圳ADI的D/A转换器的负责人怎样联系？thanks! |
| [答：Jing] |
You can refer to our AD5224,AD5225 and AD5226.You can contact with our
Shenzhen representation at 0755-83783430(Mr.Zhang Xinming). |
[2003-10-30 11:34:42] |
| [问：samire] |
单电源和双电源的DAC在性能有何区别? |
| [答：MelConway] |
Unipolar = single supply compared to Bipolar = dual supply
DACs:Unipolar is cheaper and simpler [only 1 power supply], and is
suitable for battery powered equipment. It is typically lower power [as it
uses only half the supplies of a bipolar DAC].However the signal has
no ground [unless you setup a pseudo ground, which is not optimal] which
makes it unsuitable for AC and control [+/-] type applications. The
voltage swing on the output is typically less than half that of a bipolar
output which reduces the dynamic range, Signal to Noise Ratio, and the
size of the Least Significant Bit LSB which makes it unsuitable for high
precision, high accuracy applications. As the IC Integrated Circuit has to
withstand much lower voltages, the feature size can be reduced, reducing
the die size and therefore cost.Bipolar DACs are necessary for AC,
control and any high precision or high accuracy applications whre
performance is important. Modern voltage doubler and inverter ICs [based
on charge pumps etc.] can generate the necessary negative and high
voltages for bipolar DACs at very little cost whilst maintaining all the
performance advantages.Depending on the application a very rough split
would be to use unipolar DACs at 12bits and below, and bipolar DACs at
12bits and above, however everything depends on the actual
application.Please conatct our Application Engineers who will be happy
to explain further and make part recommendations. |
[2003-10-30 11:34:47] |
| [问：stick] |
能否解释一下DAC中INL，DNL，SFDR等指标 |
| [答：LiaoWS] |
Please find them from page 15 of the presentation. Also, you can find
their specification from our datasheets. For details, please send mail to
china.support@analog.com, they will be happy to help you. |
[2003-10-30 11:35:23] |
| [问：snailman] |
请问，在精度要求很高的场合，在模数转换器的参考源选择及外围电路的设计上有哪些需要考虑的因素呢？比如是选用转换器自身提供的参考源好呢还是使用外部参考源好呢？谢谢 |
| [答：William] |
One needs to use a high performance power supply and
reference. Both the power supply and reference should be
decoupled to a quiet analog ground with two decoupling capacitors (one for
high speed noise and one for voltage stability). External
reference typically provides a better performance. |
[2003-10-30 11:36:15] |
| [问：liuhuaker] |
主持人你好，请问DAC的转换速度是通过哪个参数体现的。 |
| [答：LiaoWS] |
you can find their MSPS, settling time. For low speed DACs, it is
important to know its settling time. |
[2003-10-30 11:36:21] |
| [问：WANGGYU] |
96khz音频输出可以选择贵公司的那种类型的DAC，请教国内常用的供货稳定的一种 |
| [答：William] |
Our AD1853, AD1955, etc. can support 96kHz. In fact, AD1955
is one of the best audio DAC available on the market. |
[2003-10-30 11:38:41] |
| [问：wffae] |
D/A输出电压会受负载的变化而受到影响吗？ |
| [答：Mariah] |
The output will be influence by the load. If you drive a heavy load,
you should add a buffer at the output of the DAC. |
[2003-10-30 11:39:08] |
| [问：lijianhong] |
怎样配置一个D/A电路，使输出为双极性电流？ |
| [答：LiaoWS] |
For bipolar voltage output, you have to select the right kind of DAC.
Another way is to use the bipolar amplifiers to implement the current to
voltage conversion. |
[2003-10-30 11:39:11] |
| [问：nilibi] |
请问时钟抖动对DAC的影响有多大，有没有公式，谢谢 |
| [答：Theresa] |
Jitter causes a voltage error which is a function of slew rate and
results in an overall degradation of SNR.Theoretical SNR =6N
+1.76dBwhere N=resolution |
[2003-10-30 11:40:13] |
| [问：jikjikjik] |
有那些接口形式可选择? |
| [答：Mariah] |
Basicly, SPI, I2C for serial port and parallel port. |
[2003-10-30 11:40:45] |
| [问：jikjikjik] |
请问常用的关于声卡使用的DAC/ADC产品有那些?价格如何/谢谢 |
| [答：William] |
We have a family of SoundMax AC97 codec (such as the
AD1885). If you are looking for general purpose codec, then our
AD73311 or AD73322 are suitable. |
[2003-10-30 11:41:13] |
| [问：wffae] |
D/A芯片的复位是什么意思？D/A芯片会复位吗？ |
| [答：LiaoWS] |
It means that when power on, a fixed lotage level will be set. The
reset for the DAC is useful for some applicaitons. |
[2003-10-30 11:41:52] |
| [问：huhuizhu] |
What specification of DAC can presents the
difference of settle time from a voltage level to another one on different
voltage level? |
| [答：MelConway] |
This is a combination of Settling Time and Slew Rate. Settling time
gives the time for the output to stabilize given a certain [specified]
step size [typically full scale]. Settling time can range from 2-100us for
Voltage output DACs to 30-500ns for Current output DACs. Slew rate is the
maximum rate of change of the output - example 5V/us means that the output
can change a total of 5V in 1 microsecond [us]. If the output was at 1V it
could move to 3.5V [a change of 2.5V] in 0.5us. |
[2003-10-30 11:42:37] |
| [问：QZDZ] |
请介绍一下,现在DAC在虚拟仪器方面的应用情况 |
| [答：Wayne] |
Most application of DAC in virtue instrument should be multi-channel
DACs. So, AD53xx, AD54xx, AD55xx are big family for your choices. For
exmaple, AD5380 can reach 40 channels 14bit. While, AD5391 is 16 channels
12 bit DAC, AD5392 is 8 channels 16 bit DAC. |
[2003-10-30 11:43:07] |
| [问：peng-kai] |
在DAC与放大器一起构成程序控制放大器时，除了精度位数以外，我应当还考虑写什麽技术指标。谢谢 |
| [答：William] |
The DC specifications are important in this
application. One should look at offset, gain error, drift (if
temperature is important), etc. |
[2003-10-30 11:43:58] |
| [问：wffae] |
请问贵公司有集成温度补偿的D/A芯片吗？通常能保证的温度范围是多少？
thanks!! |
| [答：LiaoWS] |
We have not this kind of DACs. We can insure our temperature range
from 0-70 degree to the military standard. |
[2003-10-30 11:44:16] |
| [问：jikjikjik] |
请问那一类DAC适合做比精度较高的仪表器件? |
| [答：Theresa] |
The most suitable DACs for high precision instrumentation are
generally DACs with greater than 12 bits resolution, 16 bits resolution is
best choice.Bipolar dacs or Iout Dacs may be good options
depending on the customer requirements. |
[2003-10-30 11:44:35] |
| [问：lwbence] |
如果要想达到20bit以上的精度，对电源的要求如何（如果不考虑外部噪声，只考虑电源引入的），是不是只能用电池供电 |
| [答：Jing] |
We can provide 16 bit resolution DAC such as AD5543 and AD5544 now.
You can use the battery or other power supply.But you should pay more
attention to the decoupling circuit and the stability of the reference
.Thanks! |
[2003-10-30 11:44:47] |
| [问：de88] |
选择转换器时,在EMC方面应注意哪些问题. |
| [答：Gary] |
A lot of EMC compatibilty is based on system design and not just
component selection.PCB Grounding, Layout and decoupling of power
supplies have a big effect on Succeptability and Emissions. System
shielding also has a big impact on this. There are a lot of articles
written on design techniques to minimise EMC. please read the following
article for more
information.
http://www.analog.com/library/analogDialogue
/archives/30-4/EMC_CE.html |
[2003-10-30 11:45:01] |
| [问：windytj] |
DAC芯片选择时其转换速度与精度如何权衡才能得到最便宜的芯片？谢谢 |
| [答：LiaoWS] |
The simplest way for you is to give ADI a call, we can select one for
you. Our contact way is 800 810 1742. |
[2003-10-30 11:45:39] |
| [问：hobodom] |
请问专家，在D/A应用过程中，内部参考电压和外部参考电压优劣怎样？应该如何选择？对无杂散动态范围得影响是什么？ |
| [答：Mariah] |
Generally speaking,internal reference is not good as external
reference. If the specification which can be get from the datasheet is not
good enough, you should use an more accurate reference. The main parameter
for reference is the initial accuracy,temperature drift,noise etc. The DC
performance of reference will not influence SFDR while AD performance will
influence SFDR more. |
[2003-10-30 11:46:49] |
| [问：Lawson_jian] |
请问，低通滤波于A/D和D/A之间的匹配要注意那些问题 |
| [答：LiaoWS] |
Pay attention to the impedance match, the signal bandwidth, voltage
range. |
[2003-10-30 11:47:29] |
| [问：lwbence] |
对DA而言，一般场合是用内部参考源还是外部参考源？如果是外部的，一般电源芯片的输出可以吗？ |
| [答：LiaoWS] |
Normally, you can use internal reference. If you want to use external
reference, please don"t use the power supply parts, you can consider our
ADRxx series of reference parts. |
[2003-10-30 11:49:10] |
| [问：hardyye] |
dac 的精度于速度有什么关系 |
| [答：Theresa] |
There is no direct relationship between accuracy and speed of a
DAC.Current output DACs are much faster settling in ns in contrast
to voltage output dacs, settling in ms. Both types are
available with 16 bits of accuracy. |
[2003-10-30 11:49:37] |
| [问：快捷方式] |
据说现在市场上有18bit以上的DAC，不知贵公司有没有这样的产品？若有能否给一些介绍？ 顺便问一个不相关的问题，在一篇文章上看到ADI有一款运放AD8751，但在ADI主页上看不到这个型号，这是怎么回事？ 谢谢！ |
| [答：Wayne] |
Normally for DACs with resolution higher than 16 bit are audio DAC
with Sigma-delta technology. AD185x is good which can support various
sample rates.Could you contact with 8008101742 for the amplifier part#
you mentioned ? |
[2003-10-30 11:49:41] |
| [问：982441] |
现有的D/A转换器转换速率最快能达到多快？ |
| [答：LiaoWS] |
For ADI, the fastest is 500MSPS. They are AD9782/4/6. |
[2003-10-30 11:49:47] |
| [问：wffae] |
用多通道D/A输出时，如何避免在同时工作时，每个通道受其它通道的干扰？ |
| [答：Albert] |
There are generally two mechanisms contributing to crosstalk. The
first is internal to the device relating to its internal design. The
component vendor generally looks after this crosstalk mechanism minimizing
as much as possible in the layout phase of the design by incorporating
isolation between channels, avoiding interraction of the analog and
digital sections and paying attention to clock distribution etc,.The
second mechanism relates to the use of the product in the end user
application. Paying attention to layout, isolating channels with analog
ground and good decoupling of the supplies will help minimize
crosstalk.Its also important when using fast digital logic in the
interface to avoid overshoot and undershoot on the signals as this couples
acorss the device effecting performance. |
[2003-10-30 11:50:24] |
| [问：chenpld] |
ad和da连接起来时，在给定的采样速率和量化比特数时，决定系统的信噪比的关键因素? |
| [答：Jing] |
You can refer to this equation:1. SNR [dB] = 20 x log (2^(n-1) x
√6)2. Approx = 6.02n + 1.76The ideal SNR is affected by the
resulotion. But in the real world, you should minimize the noise such as
EMI and be aware about the layout and the decoupling circuit. |
[2003-10-30 11:50:37] |
| [问：candid] |
请问设计pcb时，都有哪些措施降低噪声对dac的影响？ |
| [答：MelConway] |
Use good high frequency decoupling capacitors [multi layer ceramic
etc. connected with the shortest possible leads directly to the DAC supply
pins and grounds.Use single point grounding of separate Analog and
Digital grounds.Use ground planes under and around the DAC.Do not
route any digital signals near or parallel to any analog
signals.Shield or decouple any high impedance nodes.Use filtering
on the output and reference inputs if necessary.Minimize all
impedances and resistances.Minimize over- and under-shoot, and ringing
on digital lines. Use line matching and termination if necessary on high
speed lines. Limit slew rates on digital signals.Limit siganl and
reference bandwidths. |
[2003-10-30 11:50:38] |
| [问：drly] |
您好！请问应用在微小型系统上的数模转换器都有什么型号？尺寸是多少？以此设计声频信号发生器还需要注意什么？ |
| [答：William] |
You can look at the 16-bit products for highest
accuracy. AD5570 would be well-suited for this
application. It"s available in 16 pin SSOP package. |
[2003-10-30 11:51:31] |
| [问：falling74] |
请问专家，DAC的数字端和模拟端的地怎样连接时，效果比较好 |
| [答：Wayne] |
A good PDF book for your reference:
http://www.analog.com/technology/amplifiersLinear
/training/sensorSignal.html |
[2003-10-30 11:52:15] |
| [问：qiangnet] |
能否推荐一个10M/8BIT的并行D/A转换器？ |
| [答：Mariah] |
AD9709 8bits, 125MHz,parallel D/A |
[2003-10-30 11:54:38] |
| [问：q31488] |
能问问光驱或影碟机里数模转换器的型号、功能吗？ |
| [答：Wayne] |
Could you contact with ADI toll-free phone 8008101742 for details ? we
need to know channel#, resolution#, and interface your system
requires. |
[2003-10-30 11:55:14] |
| [问：haoyangd] |
请问在Delta-Sigma
DAC中主要的技术指标常常是SNR,THD,GainError,等等，而不是常见的DNL,INL,为什么？另外这两种指标之间有没有可以替换的公式？谢谢。 |
| [答：LiaoWS] |
The reason is that Sigma-Delta DACs maily used in audio, which doesn"t
care the INL/DNL DC specs. There is no equations among them. |
[2003-10-30 11:55:19] |
| [问：wistful] |
ADV7189何时能批量供货? |
| [答：Wayne] |
ADV7189 schedule to production in November 2003. |
[2003-10-30 11:56:22] |
| [问：姚黎锋] |
请问：目前的DAC芯片所能适应的环境温度在哪个范围内？ |
| [答：LiaoWS] |
ADI can provide parts in almost all temp range, from 0-70 to -55-125
degree. Please refer to their datasheets. |
[2003-10-30 11:56:34] |
| [问：lxl9726] |
请问A/D、D/A的转换精度现在最高是多少位？谢谢！ |
| [答：LiaoWS] |
Both 24-bit accuracy. |
[2003-10-30 11:57:17] |
| [问：weijie_lee] |
ADI有没有串行接口的大于12位的DAC芯片？ADI的芯片为什么好多都没有库存？DAC的方式哪一种最先进？ |
| [答：William] |
AD7846 etc. fits your requirement. One cannot say that one
structure is more advanced as each type of structure is designed to
optimize certain specifications. We do try to provide fast
delivery of our products to customers. Many of our products are
now available without a long lead time. |
[2003-10-30 11:57:51] |
| [问：thep
rimegod] |
讲的非常好。为了使输出平滑，数模转换器的输出是不是需要接一个电容，那么这个电容应该怎样选择呢？谢谢！ |
| [答：Mariah] |
Please reference the evalution board of the dedicated DAC
part. |
[2003-10-30 11:58:58] |
| [问：join-lin] |
我们在选择D/A器件时，对精度的选择要如何判断？ |
| [答：LiaoWS] |
It is decided by youy system requirement. For example, some system
needs 16-bit resolution, but for some systems 8-bit is enough. You can
discuss your applicaiton with us via 800 810 1742. |
[2003-10-30 11:59:02] |
| [问：汉山] |
在MCU控制的录放音系统中，如和选择A/D和D/A？谢谢 |
| [答：William] |
Depending on your performance requirement, you can choose either the
mono codec AD73311 or stereo AD73322. |
[2003-10-30 11:59:33] |
| [问：kyt1999] |
对与DA转换器的精度一般如何计算和选择,对DA转换器布线是数字地和模拟地是否必须绝对分离,单点相连? |
| [答：Wayne] |
DAC accuracy depends on DAC architecture and the actual sample rate
you"re using. Basically you need to know what"s the SNR requirement you
must leave for DACs, then the effective resolution can be calculated by
ENOB=(SNR-1.76)/6.02.Single ground should be used for DAC as it"s
mixed signal chip. You can refer to below
book:http://www.analog.com/technology
/amplifiersLinear/training/sensorSignal.html |
[2003-10-30 12:00:18] |
| [问：nilibi] |
精度和分辨率的区别 |
| [答：LiaoWS] |
Jingdu is accuracy, Fenbianlu is resolution. Resolution means how many
bits, accuracy means INL/DNL specs. |
[2003-10-30 12:01:40] |
| [问：TSZ889] |
请问DAC适用于频率高的电路吗 |
| [答：LiaoWS] |
Of course. We have TxDAC series of DAC used in base station and
handset. |
[2003-10-30 12:02:21] |
| [问：jikjikjik] |
有那些比较通用的8位DAC产品?价格如何? |
| [答：William] |
AD5424/5/6 etc. are all 8-bit DAC. Please check with our
distributor regarding its price as it is related to the quantity. |
[2003-10-30 12:03:34] |
| [问：guorock] |
一般AD公司的芯片承受过载的能力如何？10000个g的加速度能承受吗？ |
| [答：LiaoWS] |
Our MEMS parts can tolerate 3500g. But for normal parts, they cannot
tolerate 1000g. |
[2003-10-30 12:03:35] |
| [问：jikjikjik] |
请问,什么DAC/ADC是多通道的?如何选择此类器件? |
| [答：Wayne] |
We"ve very big family of multi channel DAC/ADC like AD538x, AD539x,
AD7689/7998...... Also we"ve multi channel ADC and DAC and MCU integrated
chip ADuC8xx.If you need to select a proper part, please call
8008101742 to give your system requirement including resolution, sample
rate, interface.... |
[2003-10-30 12:03:37] |
| [问：lijianhong] |
How to use D/A converter to get a current
output from -10mA to 10mA? IS it need a V/I converter such as
AD694? |
| [答：Albert] |
The AD694 will only allow unipolar output current of o to 20mA.A
more efficient and cost effective method of generating a bipolar current
is to use a bipolar voltage output DAC in conjunction with an external
amplifier configured as a Howland current pump to generate the bipolar
current control. |
[2003-10-30 12:03:38] |
| [问：smx
64098] |
请问D/A本身所代运放的驱动能力有多大？ |
| [答：Theresa] |
The output of the op amp is low output impedance. |
[2003-10-30 12:03:42] |
| [问：0206
47319] |
请问使用了数模转换器的电路在电磁兼容试验中有什么需要注意的吗？ |
| [答：Gary] |
The digital Inputs and Outputs can be the cause of a lot of EMI, this
is true for transient discharges to enter a piece of equipment, and for
interfering signals to escape, either by conduction of spurious signals on
the I-O lines or by radiation from the I-O cable. Because of this, the EMC
performance of the I-O port is crucial to the EMC performance of the
entire package.For succeptibility, You should check that the
output voltage goes to the correct expected value, this will ensure that
the interface is robust. Also check how much of the interference is being
coupled onto the output, and where it is getting coupled
through. |
[2003-10-30 12:03:54] |
| [问：stick] |
设计低位数（4位），高速（250M以上）的DAC一般采用什么结构？ |
| [答：Albert] |
Current Source based DAC for speed. |
[2003-10-30 12:04:28] |
| [问：cby9
81541] |
高档计算机数字音箱设备使用什么类型的D/A转换器比较好？ |
| [答：William] |
Our AD1885 etc. are used very widely as the SoundMax AC97
codec. |
[2003-10-30 12:04:35] |
| [问：samire] |
SFDR,THD和速度之间的关系如何处理?因为视频应用的高速CMOS
DAC的SFDR和THD都较差.有何好的解决方法? |
| [答：Wayne] |
You may find proper product in ADI catalog, like ADV7123 DAC,
ADV7171/ADV719X/ADV73xx as video encoder.You can call 8008101742 to
give details of your application, our engineers will help you on part
selection and design support. |
[2003-10-30 12:07:21] |
| [问：648919] |
ΣΔ ADC的规格说明常常假定 某一输入时钟频率，从而也就规定了
采样速率。如果使用的时钟频率高或低于规定值，那么我能可靠地使用这种转换器吗? |
| [答：LiaoWS] |
Normally, there is a clock range for the parts. Use the clock in this
range should be no problem. |
[2003-10-30 12:07:23] |
| [问：yang
yang23] |
高质量的音频输出 考虑做成Hiend推荐采用那种dac好？
请告知 |
| [答：William] |
AD1955 is regarded as the industrial performance leader for audio
DAC. ADI has many audio DAC which are used in hi-end
audio. Please refer to our selection guide for
details. |
[2003-10-30 12:07:57] |
| [问：qin] |
如何考虑高速DAC的接地?多少位的DAC需要认真考虑? |
| [答：Mariah] |
Please reference the book "High Speed Design Techniques" which can be
downloaded from ADI website. www.analog.com |
[2003-10-30 12:08:28] |
| [问：johnling] |
请问音频DAC有哪些最新型号? |
| [答：William] |
AD1955 is the latest one. AD1853 is also quite
popular. |
[2003-10-30 12:09:39] |
| [问：johnling] |
We design digital mixer, which kind of DAC
you will recommand to us? |
| [答：LiaoWS] |
Please let us know your bandwidth, SFDR, SNR requirement. Then we can
help you on your case. Please contact china.support@analog.com or the
toll-free number 800 810 1742. |
[2003-10-30 12:11:33] |
| [问：wffae] |
请问目前有没有不需reference voltage
D/A产品？thanks!!! |
| [答：Mariah] |
What do you mean no reference voltage D/A? Does that mean no external
reference voltage? We have a lot of parts with internal reference such as
AD667,AD767,AD7233 AD7243 etc. |
[2003-10-30 12:11:50] |
| [问：zjg18] |
请推荐最常用的12位串行dac/adc |
| [答：Wayne] |
If you use MCU, I"ll suggest you use ADuC812/831/832/841/842, which
integrates 8051 MCU plus 12 bit ADC with MUX, 12 bit DAC.We"ve big
family for 12bit ADC, like AD78xx, and 12bit DAC as well like AD532x. It
depends on what sample rate you need as well. |
[2003-10-30 12:12:52] |
| [问：ljp] |
什么是量化噪音?不同分辨率的DAC,其量化噪音有何不同? |
| [答：LiaoWS] |
quantilization noise is inherent to the converters. For different DAC,
the quantilizaiton noise is different. Please refer to page 54 of the
presentation. |
[2003-10-30 12:16:01] |
| [问：roa
mingsky] |
DAC的转换时间取决于哪些方面，ADI公司的产品最短可以达到多少时间，具体有哪些型号，thanks！ |
| [答：LiaoWS] |
It is decided by the architecture. Our fastest is 500MSPS, they are
AD9782/4/6. |
[2003-10-30 12:17:46] |
| [问：lucawrj] |
请专家谈谈影响D/A转换精度因素和相应采取的措施 |
| [答：MelConway] |
The factors are internal and external.Internally architecture, fab
process, and design all contribute to accuracy. Accuracy may also be
improved by trimming [laser or other means] or calibration. Low offset
output amplifiers are necessary.Externally the Reference must be
carefully selected to give required performance over temperature [ppm/oC].
Minimize temperature excursions. Use high quality components with low TC
Temperature Coefficient.Accuracy depends on Resolution, higher
resolution DACs are typically [but not always] more accurate. Choose a DAC
with INL Integral NonLinearity of 1LSB Least Significant Bit or smaller
for best linearity. beware of INL [also known as Relative Accuracy] which
is specified in percent % of Full Scale - older DACs may have been
specified in this way but newer parts do this often to hide poor
accuracy. |
[2003-10-30 12:17:58] |
| [问：wffae] |
请问：有种产品需8Bit
D/A,但输出容易受电源的纹波影响，有没有一种不受电源纹波影响的D/A芯片啊？ |
| [答：Wayne] |
AD530x/533x can be good choice. But, all ICs can be affected by power
supply ripple. Therefore, you need always choose good DC/DC or LDO (ADI
has good products ADP3xxx). Also, you need to do good power supply
de-coupling according to general rules, or the datasheet of the DACs. For
details of the rules, you can refer to:
http://www.analog.com/technology
/amplifiersLinear/training/sensorSignal.html |
[2003-10-30 12:18:07] |
| [问：dengxy1960] |
目前高校实验一直沿用0832,请推荐几款物美价廉的DA芯片 |
| [答：Mariah] |
AD5300,AD5301,AD5330,AD5331 etc.You can dial the toll-free number
800-820-1742 to get ADI products short form. |
[2003-10-30 12:18:51] |
| [问：andrewpei] |
请问在选择高精度的DAC时，与选择普通DAC有何不同的地方，应着重哪些技术指标。另外，并行输入口和串行输入口的DAC，哪一种抗噪声能力更好一些，对于数字IO，应该采取些什么隔离措施呢？谢谢 |
| [答：William] |
The high accuracy DAC will of course have better
specifications. One should look at the DC specifications such
as offset, gain error, temperature drift, DNL, INL,
etc. Parallel or serial I/O won"t make much difference in terms
of resistance to noise. However, many people found parallel
port to be easier to use because the speed is much
lower. Digital lines should be kept as far away from the signal
line as possible and separate ground should be used. |
[2003-10-30 12:19:12] |
| [问：tugang0731] |
你好：我曾经使用过adc0809和dac0832,这为两种比较常用的芯片，但现在我想用一些高精度的模数转换元件，请问该选用什么型号的比较好！ |
| [答：William] |
Depending on your application, please refer to our selection guide
based on your accuracy needs. |
[2003-10-30 12:20:33] |
| [问：吕毅] |
要实现高精度的数摸转换，最值得注意的地方除了好的电源和对模拟信号的保护外还有什么啊 |
| [答：Wayne] |
At first, you need high performance DAC,then except power supply,
and protection, you need to follow other ruls of PCB layout. You can refer
to below book for the rules:
http://www.analog.com/technology
/amplifiersLinear/training/sensorSignal.html |
[2003-10-30 12:20:50] |
| [问：qin] |
在PCB
Layout时如何对产生噪音的元件如电容,开关电源,磁性元件等元件进行屏蔽以增加动态范围?这种屏蔽如何和地线相连?在什么地方相连最好? |
| [答：LiaoWS] |
You can place them far away from your parts. And shield them if
necessary. The shielding should be connected to AGND. The GND should be
connected at the power supply as the common one. |
[2003-10-30 12:21:37] |
| [问：youzidu] |
请问如何更好的选择AD公司的sigma-delta 数模转换器？ |
| [答：William] |
Please tell me specifically what application in which are you
interested. Sigma-delta DAC are used mainly in
audio. If that"s the application you need, then DNR and THD are
the most important specifications. |
[2003-10-30 12:22:02] |
| [问：刘润秋] |
sip及iic接口传输距离是多少？ |
| [答：LiaoWS] |
It is decided by the wires you used. And should be decided by your
system design. |
[2003-10-30 12:22:32] |
| [问：dairlom] |
先生你好：我现在正打算做一个8位的D/A转换，要求的较高线性度；速度可以不用太快（10K左右）；能直接电压输出；输出极性有单级性和双级性两种。谢谢！ |
| [答：Mariah] |
AD5530 12bits,voltage output, bipolar output |
[2003-10-30 12:22:47] |
| [问：johnzhou] |
DAC输出不稳定经常出现跳变（跳到峰值），该如何防止这种情况发生。 |
| [答：William] |
This is not a normal behavior for precision DAC. You can
try reducing the load current by adding external buffer. |
[2003-10-30 12:23:03] |
| [问：samire] |
高速DAC在PCB布局设计时需要考虑那些因素,以降低寄生参数的影响? |
| [答：LiaoWS] |
How fast is your DAC and data lines. One common way is to use
multilayer layout and use more gounds. |
[2003-10-30 12:23:23] |
| [问：lhg100] |
DAC 与
PWM做的电流输出在应用的差别？？？（有些芯片如PIC自带多路PWM,这样很有价格优势） |
| [答：Jing] |
You can refer to our ADuC831/2/4. There is DAC output together with
PWM output. The PWM can be configured as a Sigma-Delta DAC and other
application. |
[2003-10-30 12:23:27] |
| [问：haoyangd] |
我想继续问DeltaSigma DAC的指标的问题：一般情况下，DeltaSigma
DAC是应用在音频领域，但是我知道ADI有一个产品AD421是应用在工业控制领域，它的指标就是以INL提出来的，那么在设计时是如何测试该指标的呢？我在做类似的设计，但是对如何测试DeltaSigma
DAC的INL指标有疑问，特此提出，希望能给予回答。 |
| [答：Albert] |
INL or integral non linearity basically tells the user the error
between the actual and ideal output for a D/A converter.From the
design we can generally predict at which codes the worst case INL occurs
and test for these as part of the final test. Therefore in
testing a specific code is loaded to the DAC and the output voltage
measured, the difference between the measured and the ideal after taking
out the offset and gain error results in the INL error and this is
generally specified in lsbs or percentage of fullscale. |
[2003-10-30 12:24:14] |
| [问：zhai
shenghua] |
您好，我正在使用贵公司的12-Bit, 125MSPS DAC
AD9752,请问，在电路设计中有什么需要特别注意的地方？ |
| [答：LiaoWS] |
The simplest way for you is to refer to the evaluation board schematic
and layout. any technical support needed, feel free to contact 800 810
1742 or china.support@analog.com |
[2003-10-30 12:24:20] |
| [问：cobuild] |
我想选用一种数模转换器，要求工作电压为+5V，12位并口电压输出，两路或者四路输出，请问ADI公司的产品中有哪些可以选用？价格分别是多少？ |
| [答：Wayne] |
AD5342/3 (12bit, dual DAC), AD5344 (QUAD 12bit DAC) is good choice.
For price, please contact with local ADI office, or ADI
distributor. |
[2003-10-30 12:24:54] |
| [问：wistful] |
在进行DA转换时,器件已经选定,如何通过布线来提高信噪比? |
| [答：Mariah] |
The best way is to reference the PCB layout of the evalution board of
the dedicated part. |
[2003-10-30 12:25:13] |
| [问：lyz_b
lue_sky] |
在国内，有很多像我这样经验很欠缺的技术人员，在选择DAC时，不知如何选择，对很多参数理解得不够深刻，如何缓解这些问题？ |
| [答：LiaoWS] |
OK, you can call us by 800 810 1742, or send mail to
china.support@analog.com. We will be very happy to help you. |
[2003-10-30 12:25:15] |
| [问：candid] |
设计电路板时，如何才能保证d/a，a/d的精度不受影响？ |
| [答：Wayne] |
There"re various rules that you need to
follow:http://www.analog.com/technology
/amplifiersLinear/training/sensorSignal.html |
[2003-10-30 12:25:38] |
| [问：ljp] |
16位30MSPS的DAC,DNL为什么只有14位?14位的DNL是否意味着是非单调的? |
| [答：William] |
A 14 bit DNL in a 16 bit DAC means the part is NOT
monotonic. Montionicity requires DNL to be within
1LSB. To achieve both high speed and accuracy is
difficult. DAC with this kind of speed is usually used in
communication system. Monotonicity is usually not required in
this application. |
[2003-10-30 12:26:01] |
| [问：662135] |
How about D/A transfer
resolution? |
| [答：Mariah] |
What does "TRANSFER" resolution mean? |
[2003-10-30 12:26:22] |
| [问：chen
xinyu009] |
选择数模转换器有不有更快捷的方式 |
| [答：LiaoWS] |
Call the toll-free number 800 810 1742. It will be fast, and we have
selection guides ready for you, we can send them to you if you can let us
know your address. |
[2003-10-30 12:26:30] |
| [问：chen.wei] |
有用于高清晰度电视系统的DAC吗，是什么型号？ |
| [答：Wayne] |
I think you means video encoder, then we"ve good performance parts
like ADV7195/6/7 supporting HDTV. We"ve also ADV73xx which support both
SDTV and HDTV. |
[2003-10-30 12:27:36] |
| [问：grey_
yz1949] |
我正在用FPGA控制DAC0832。产生正弦信号采用查表法，但是总是在过零点的时候有较大的毛刺，请问是0832内部的问题吗 |
| [答：William] |
DAC0832 is a rather old part. I suspect this is caused by
switching of the internal driving circuit. |
[2003-10-30 12:28:00] |
| [问：wffae] |
为了保证高精度，在PCB layout
方面应特别注意些什么？thank!!! |
| [答：LiaoWS] |
Design with good decoupling, good grounding method, use the right
power supply. And make sure to refer to our evaluation board schematic and
layout. For technical support, call 800 810 1742, or send mail to
china.support@analog.com |
[2003-10-30 12:28:27] |
| [问：SHIFENG] |
选择数模转换器需要考虑哪些外部因素？外部环境对器件本身有没有影响？ |
| [答：Jing] |
You should pay attention to the environmental temperature and the EMI
. It"s will bring the temperature drift to the device
. |
[2003-10-30 12:30:42] |
| [问：kzw] |
除了sigma-delta型的DAC之外，还有什么型的DAC? |
| [答：William] |
There are others such as R-2R (sting DAC) and voltage divider
type. |
[2003-10-30 12:32:19] |
| [问：tuo
lang2000] |
在数模转换器中其转换频率和器件的采样周期是否相同，在设计D/A变换的时候，怎么才能避免EMI的问题 |
| [答：Jing] |
It"s different. You should pay attention to your PCB layout such as
decoupling and seperate the analog from the digital GND etc. |
[2003-10-30 12:32:46] |
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