LTC2333-16

Hi

I have created a circuit board with LTC2333-16 and a FPGA (xilinx 6). I have problem with LTC2333-16 that data value part of SDO flicker even if the analog input is fixed to ground.

I only use channel 0 in my test setup and ciruit board use CMOS I/O mode. I have followed the user guide when creating the board and picture of schematic and PCB is attached below. I have also attached three videos showing the flickering behavior on channel 0 with softspan code set to 3'b100. The clock frequency (SCLKI) is set to 2MHz.

Thanks in advance
Stefan

I noticed in the data sheet on page 32 that minimum usable frequency on SCLKI is 37MHz so I changed the frequency from 2MHz to 50MHz on SCLKI and clock look still surprisingly clean but the value on SDO still flicker. I have attached videos showing signals on oscilloscope and logic analyzer with this new frequency where SDO has the same appearance as when frequency was 2MHz.
[edited by: hybridsynth at 12:54 PM (GMT -5) on 2 Jan 2024]