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AD9625  can not work

Question asked by wushuang on May 24, 2017
Latest reply on May 24, 2017 by JudyChui

Hi

   

My design is four AD9625 chips working at 2.4GHz sampling frequency, the clock is provided by a HMC7044 chip. After sampling the data sent to the FPGA, AD9625 TX JESD204B protocol configuration for the 8 LANES, F = 1, K = 32, Scrambling. The FPGA receiving section of the JESD204B IP uses the same configurations.

However, the situation I encountered was that the SYNC signal at the FPGA receiver was always logic 0. We can receive K characters from the physical layer of GTH.

Then, I measured the AD9625's supply pin voltage (4 AD9625 parallel power supply, current is not restricted) and found that when the AD9625 in RESET mode, the pin voltage is normal, when the AD9625 work, the pin's supply voltage drops 0.12V (FROM 1.26 DOWNTO 1.14).      

I guess:

  1. AD9625 bad (very unlikely)
  2. The clock generated by the HMC7044 may have an unknown failure (since the AD9625 pin supply voltage is also normal if we do not enable the 2.4GHz clock).
  3. Assuming AD9625 operation, the supply voltage is 1.14V normal (the minimum on the datasheet is 1.26V), I may not have the AD9625 JESD204B protocol correctly configured.

    Now, I think the above speculation is not correct, but I could not find other reasons. Can you give me some help to solve this problem? Thank you!!!

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