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Selvaprasad , 08-05-2023, 06:46 AM

Hi,
In DDR4 schematics, I have seen that there is connection between vcc_1v2 voltage and vtt_0v6 voltage through a capacitor. We provide core voltage and termination voltage through different power IC, then what is the need for connecting two power rails with capacitor.

Robert Feranec , 08-05-2023, 07:02 AM

I believe this may be influenced by PCB layout and stackup and it can take into consideration what planes are used as reference planes for signals. (simply to say, means these capacitors will be "shorting" these planes for some frequencies for better return current path). But this is only my theory.

Selvaprasad , 08-05-2023, 08:07 AM

Thanks, so it may acts as stitching capacitor

Robert Feranec , 08-07-2023, 05:26 AM

I think, but I may be wrong