AnsweredAssumed Answered

AD9265-FMC-125EBZ Eval Card Conversion

Question asked by marcomercuri on Jul 27, 2017
Latest reply on Aug 3, 2017 by marcomercuri

Hi all,


I'm interfacing the AD9265-FMC-125EBZ Eval Card with the PicoZed.


I'm using external pin mode configuration (i.e., configuration without SPI). I'm using an external clock at 10 MHz and I'm operating un CMOS mode. I'm having some issue with the acquisition. 


I'm experiencing that if I apply signals within 1.8 Vpp, pins D11, D10, D9, D8, and D7 are fixed to 1. This means my input signals will be "quantized" with steps of about 4096 (meaning about 0.125 V). This is an example with triangular signal at 100 kHz as input (I get 1024 samples each acquisition):



Those pins goes to 0 only when I'm applying input signals from 0-2 Vpp:



This is when I do not apply any signal. The conversion seems correct oscillating around Vref= 1V. However, in this configuration it is probable that those pins (D11 downto D7) should be 1.


Do you have any suggestion? Is it possible the AD9265 chip is damaged?


Thank you very much.


Best Regards,