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Ad9914 SYNC_CLK problem

Category: Hardware
Product Number: ad9914
Software Version: ISE14.7

Hi, We are using AD9914 in our board. After power up,we set the master reset to 1 to reset the ad9914,then we set the  master reset to 0.we need to see the SYNC_CLK output at the pin 82. When the  temperature is 25℃,we can see it,but when  the  temperature is -40℃,we can not see the  SYNC_CLK .

Parents
  • Hi  ,

    Moving this thread to Direct Digital Synthesis (DDS) Q&A

    We were able to do a bench test for the AD9914 Eval board varying the temperature of the DUT from 25°C to -40°C and checked the output at the pin 82 (SYNC_CLK).

    So far here are our results.

    SYNC_CLK @25°C

    SYNC_CLK @-40°C

    Based on the results,  the SYNC_CLK output didn’t changed even if we vary the temperature from 25°C to -40°C. It is still showing the same output and wasn’t showing any noticeable changes.

    Here’s the overall results:

    Temperature

    Vpeak-peak

    Vp

    25°C

    1.347

    1.18

    -40°C

    1.466

    1.32

    Just want to ask if after exposing it to -40°C, is the board still working? There might be an instance that it wasn’t able to withstand such temperature or barriers when exposing the AD9914 infiltrated other components thus the reason it might be not functioning. I would also like to ask if only the part or the whole board is exposed to -40°C. In which if the whole board is exposed to -40°C, other components might not be able to withstand it.

    All the best,

    Jules

  • Hi:

         Thanks for your reply. I've been trying for days but I still can't find the problem.I want to ask which factors can affect the output of the SYNC_CLK.In my design,I do not use the adclk925 to provide the refclk for the ad9914,Instead I use the adclk946, Does it matter?My design is as follows.

Reply Children
  • Hi  ,

    I just want to ask if the whole board or just the AD9914 is exposed to -40°C? If the whole board is exposed to -40°C,you could check the current consumption of the board’s power circuit. The AD9914 might have been powered down if this board’s power circuit is not suitable for -40°C operation. Checking the ADCLK946, this part is also rated up to -40°C so it would also function under your temperature settings. 

    Regards,

    Jules