DS90CR287: Serial output clock from SERIALIZER IC

Hi Cleatus,

Could you please provide me with a capture of what you are seeing from both TXCLK_IN and TXCLK_OUT?

Best,

Nikolas

TXCLK_IN :

TXCLK_OUT :

Hello,

With regards to your TXCLK_OUT capture, what you seem to be observing is radiated emissions, not the clock itself. These emissions won't be at the actual frequency of the clock, but rather a harmonic of your clock frequency. The 175MHz peak you are referring to is a harmonic of the 25MHz clock frequency.

Did you intend to share a capture of the radiated emissions? Or was this simply a misinterpretation of the meaning of the TXCLK_OUT capture?

Best,

Nikolas

I tried probing TXCLK_OUT but was unable to capture any clock. Hence, when I tried probing using RF channel on the oscilloscope, I observed a peak at 175MHz. What am I suppose to observe when I probe TXCLK_OUT? What is the issue here?

Hi Cleatus,

When probing TXCLK_OUT, you should be observing your PCLK. Are you measuring the differential? Since this is LVDS, you will have to be measuring that way in order to observe the PCLK properly.

Best,

Nikolas

Hey Nikolas,

Thanks for the reply!

The issue seemed to be with the IC. I had it replaced and now I am able to probe TXCLK_OUT correctly.