Hi,
I have already posted a request untitled "Ripple on TPS56221" on February 23, 2012. I though that the problem was solved but when the processor used more ressource, the consumption increases and I seen switching frequency on my DDR data (between DDR and processor). The TPS56221 power the processor core.
To solve problem, I have replaced my TPS56221 implementation by TPS56221EVM-579 Evaluation module as illustrates the following picture.
The processor consumption was 8A under 1V in this configuration. When we check switching frequency on the scope, we see oscillation on the the 500kHz, as we can see on the following picture.
The measure was done with a very short ground on scope probe. Why this oscillation ?
We have seen on the scope that the 500kHz switching frequency of this evaluation board was synchronous with error data on DDR access between processor and DDR SODIMM.
How can I filter this oscillation ?
Does input need to be filter ? I power evaluation module with a labotary power supply.
When I read SLVU446, I don't see these oscillation on the switching frequency ? How do you do your measure ?
Best regards,
Laurent
