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AD9880KSTZ-150 problem

Question asked by LiorM on Aug 4, 2013
Latest reply on Aug 13, 2013 by DaveD

Hello.

 

I would like to describe a problem I face with AD9880KSTZ-150.

 

The AD9880KSTZ-150 is integrated in our circuit in application of Video IN (AUX. port) to the system..

 

We face problem of bringing it to work properly. All power supplies are ok, all peripheral seem to be ok, but the ic doesn't work.. We checked also the pins DATACLK(89), DE(88), PWRDN(81)..

I'm attaching also some captures from the scope measurements we had.

 

The relevant electrical scheme is attached.

 

The batch serial/code that is written on the ic is: KSTZ-150; #1241; 2469266.1.

Please help us verify that the ics' series ok.

 

Attached three captures from the scope measurements:

 

  1. 1.       yellow_89_dataclk_blue_88_DE: It's the dataclk vs. the DE pin, the unstable can be seen.
  2. 2.       yellow_89_dataclk_blue_88_DE_b: : It's the dataclk vs. the DE pin, the unstable can be seen.
  3. 3.       Blue_89_dataclk: The dataclk of the AD9880, short period that seems more like a clock. Pin 89, dataclk, doesn't work propely. It seems that the clk doesn't even get down to logic '0' when it oscillates.
  4. 4.       yellow_PWRDWN_81_blue_89_dataclk: The yellow probe shows (very-long-time-scale of 1sec) the power-down commands from the FPGA when it measures that the dataclk isn't ok. The yellow probe isn't a clock. The FPGA checks the validity of the dataclk in a known time-period, repeatedly.

The dataclk can be seen unstable..

 

 

Also, the AD9880's top cover is hot..

 

 

Thanks a lot in advance,

Lior.

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