ADV3202 - cropped video signals

Hi, Daniel.

Can you please try removing the 1K and the 68uF in the Vclamp and Vref pins respectively? These components are not in the eval board schematic.

Let me know if this works.

Regards,

Anna

Hi Anna,

thanks for your reply, unfortunately it didn't work. Could it be a problem, that VCLAMP is not connected to VREF? Which levels should both voltages have?

Thanks in advance,

Daniel

Hi Anna,

do you have any additional advice for me maybe?

Thanks in advance,

Daniel

Hi, Daniel.

What is your 193rd serial data bit? This bit enables or disables the VCLAMP. Can you please check if this is low?

Also please connect all your DGND to AGND.

Regards,

Anna

Hi Anna,

thanks for the reply. VCLAMP bit was set, I tried it with 0 but it changed nothing. Also AGND and DGND are connected.

Regards,

Daniel

Hi, Daniel.

Can you please measure the voltage in the VREF pin? From your circuit, this is 5V (contradicting your signal name of VA2P5) thus exceeds the absolute maximum VREF input voltage range of VPOS - 3.5V to VNEG + 3.5V.

If your measurement is really 5V, please remove the EMI filter bead and see if this removes the clamping.

Regards,

Anna

Hi Anna,

thanks again. I measured aproximately 2.2V (Z-Diode before bead) at VREF, but removed the bead anyways. Now I can measure a 2.3V at VREF, 2.0V at VCLAMP (both unconnected from VA2P5) and there's still no change in the video signal. Unfortunately ...

Regards,

Daniel

Hi, Daniel.

Can you please remove the capacitors at the inputs (C505 to C520) or replace them with 0 ohm resistors and see what happens?

Regards,

Anna

Hi Anna,

sorry, I forgot to mention, that I already replaced them with 0R. The video signal before was no video signal at all ...

One more thing: All activated outputs have these 900mV level, even when there's no video signal applied or routed. All deactivated outputs are constantly tied to GND. Changing bit 193 didn't change anything.

Regards,

Daniel

Hi, Daniel.

Can you please replace the 2kohms in R129 to R144 with 0 ohm resistors and the 1kohms in R161 to R176 with 75 ohms? Let me know if this changes anything.

Regards,

Anna