output. I suspect it may be related to the clamping circuit operating in a
noisy environment. When I remove the input and reinsert it, I can occasionally
get a clean signal for a split second - then something inside the ADC seems to
lock up and the noise reappears.
In this case some things to note:
For improved performance for noisy environments and bad sources the customer
should use the ADV7188 for any new designs.
Secondly we recommend a 28.63636Mhz crystal to clock both parts for best
The decoder should be programmed according to the recommended write. The
customer may be getting an output without fully programming the decoder and
hence the noisy output.
Attached is our recommended programming script for the ADV7183B.
The trace length of the LLC in is also very important.
Attached also is the evaluation note which includes an example schematic for
ADC supply decoupling and layout.