AD9680 and AD9680-1000EBZ

Hello everybody,

we would like to evaluate AD9680 1GSps ADC. After few days of reading docs and browsing AD9680-1000EBZ schematics, I'd like to ask you a few questions.

I've found the schematics of AD9680-1000EBZ here:

ftp://ftp.analog.com/pub/HSC_ADC_Apps/AD9680CE04B_Design_Support/9680ce04b_schematic.pdf

1. In schematics of AD9680-1000EBZ, page 8, there is an IC labeled U900 without any type description. On other pages (for example page 9), it is referred as AD9526. Nevertheless, I can't find any reference  to this part and it looks like that this part does not exist. Even BOM located in the same FTP directory does not know anything about U900.

2. It looks like this part is not used and all clocks must be supplied externally. Do you have any recommendations for signal generator phase noise? We have Agilent E4426B. Do you think, that this would be sufficient as clock source?

3. Do you have any recommendation for clock synthesizer IC, which would fulfil phase noise requirements for AD9680?

4. It looks like that only possible way to supply clock for AD9680-1000E is analog clock source from RF generator. Using CML or LVDS seems not possible to me with current AD9680-1000EBZ design (proper termination is missing). Is it correct?

5. I've also found some reference to evaluation board AD9680-1250EBZ. From the picture in quick start guide, it looks like this board does not have such limitations as AD9680-1000EBZ. Baluns are supplied externally, so using different clocking (CML or LVDS) should be possible. Do you have any information, if and when this board could be purchased?

Thank you very much and best regards

Petr Masek

  • 0
    •  Analog Employees 
    on Jul 23, 2014 3:11 PM

    Hello Petr,

    Thank you for contacting EngineerZone regarding the AD9680.

    Petr Masek wrote:

    Hello everybody,

    we would like to evaluate AD9680 1GSps ADC. After few days of reading docs and browsing AD9680-1000EBZ schematics, I'd like to ask you a few questions.

    I've found the schematics of AD9680-1000EBZ here:

    ftp://ftp.analog.com/pub/HSC_ADC_Apps/AD9680CE04B_Design_Support/9680ce04b_schematic.pdf

    1. In schematics of AD9680-1000EBZ, page 8, there is an IC labeled U900 without any type description. On other pages (for example page 9), it is referred as AD9526. Nevertheless, I can't find any reference  to this part and it looks like that this part does not exist. Even BOM located in the same FTP directory does not know anything about U900.

    2. It looks like this part is not used and all clocks must be supplied externally. Do you have any recommendations for signal generator phase noise? We have Agilent E4426B. Do you think, that this would be sufficient as clock source?

    3. Do you have any recommendation for clock synthesizer IC, which would fulfil phase noise requirements for AD9680?

    4. It looks like that only possible way to supply clock for AD9680-1000E is analog clock source from RF generator. Using CML or LVDS seems not possible to me with current AD9680-1000EBZ design (proper termination is missing). Is it correct?

    5. I've also found some reference to evaluation board AD9680-1250EBZ. From the picture in quick start guide, it looks like this board does not have such limitations as AD9680-1000EBZ. Baluns are supplied externally, so using different clocking (CML or LVDS) should be possible. Do you have any information, if and when this board could be purchased?

    Thank you very much and best regards

    Petr Masek

  • 0
    •  Analog Employees 
    on Jul 23, 2014 3:19 PM

    Hello Petr,

    I am sorry I pushed the wrong button last time. Here are the answers to your questions.

    1. This part has been discontinued.

    2. We use Rohde-Schwarz SMA100A with the low phase noise B22 option. The REFCLK need not be a low phase noise clock. It is just a reference frequency being fed into the FPGA board.

    3. I will send you some details in another email.

    4. Yes this is correct. For the current AD9680-1000EBZ design, the only option is to use an external single ended RF clock.

    5. That board is similar to the AD9680-1000EBZ. If you have an external differential clock, you can populate J802 in the evaluation board and remove T800, C816 and place 0ohm resistors for R806, R807. Once this is done, terminate the clock differential paths appropriately and it should work.

    Hope this helps.

    Regards,

    Umesh

  • Hello Umesh,

    first of all thank you very much for your quick and precise answers.

    1. Thank you. I though that, but it is better to ask.

    2. Thank you.

    3. Please, be so kind. I'm very interested in your opinion.

    4. Thank you.

    5. So for me it looks like that -1250EBZ would be a better choice for us. Do you have any information, when it will be available or how can it be purchased? I've googled no information except some quick start guide. Would it be possible to provide me schematics?

    6. In this forum, you've told someone, that you were preparing some reference design for Zynq. If you already have something, is there some way how to obtain this?

    One more thank you and best regards

    Petr

  • 0
    •  Analog Employees 
    on Mar 2, 2015 7:40 AM

    Hi Petr,

    I am so sorry for replying so late.

    3. I have sent you an email with information on (unreleased yet) a clock synthesizer for AD9680.

    5. I am not sure who our field applications rep is in the Czech Republic, but I have included someone in the email to you who can help with the -1250EBZ request.

    6. Can you please take a look at the ADFMCDAQ2EBZ? User guide available here.

    Please let me know if you have any questions.

    Thanks

    Umesh