AD7760 observe MCLK/2 on analogue input

Discussion created by mukuru on Aug 9, 2016
Latest reply on Aug 10, 2016 by mukuru

Hi Forum


I have recently built a board using the AD7760 ADC and find that I see some ICLK  (1/2 MCLK) on top of the ADC analogue input. In fact it sometimes appears on Vin_p and then on Vin_m, whilst the opposite input is flat. On the eval board from Analog I don't see this. Unfortunately my ADC board connector is not the same type as the EVAL board to try it on the  FPGA motherboard.


We are having trouble at the moment reading data from the ADC but it seems we are able to power up the ADC since the current increases.


I will need to follow up with some scope plots to explain this better.  However, if you have experienced something like this it would be good to know.