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 + 1.76
The 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] Σ?Δ 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]