EVAL-AD9957 board for full external control

Hi,

You can use this document as a guide in controlling the AD9957 evaluation board using full external control.

Best regards,

Mark

thanks for reply. do I need to make change on hardware of the ecal-ad9957 board to use the external control ? 

Hi,

No hardware change is needed for the EVAL-AD9957. Just disable the buffers between the USB interface and the DDS then connect ALL the required input to the headers provided on the board.

Best regards,

Mark

did you check the schematic of the eval-ad9957 board ? I think that when we disable the buffers between the USB interface and the DDS , we will no longer get the PD_CLK.

did you use try it before ? 

Hi,

Apologies for overlooking this. Yes, disabling U12 will also disable PDCLK on J8 and pin 15 of U6. A work around for this is to use a wire to jumper PDCLKBUF to PDCLKOUT or PDCLK on U12 to still get the PDCLK output on J8 and pin 15 of U6. In case that you need to use PDCLK at higher frequency (250MHz max) and there is deterioration of quality, you may refer to this thread:  RE: AD9910 EvalBoard PDCLK External control 

Best regards,

Mark