Three-terminal capacitors for EMI filtering

[aylons]

Hi!

I have an EMI problem that I've mostly solved. It is a teeny tiny noise noise coming from inside a ethernet PHY IC, around 500 MHz. By teeny tiny, I mean -130dBm after two 20dB amplification stages. But it really has an impact in out measurements, and I'm working on getting rid of it.

Some strategically placed 100pf capacitors (not in the supply pins, which already had them!) really helped in the prototype, and now I'm designing the next iteration of the board. To get really safe, I'm pondering on using these 3-terminal capacitors from Murata:

http://psearch.en.murata.com/capacitor/product/NFM15CC222D1A3%23.html

These are 2200pf caps with SRF above 1Ghz! Sounds almost too good to be true. I've already used some similar capacitors (even in the same board), but they were 0603 and not so big. Also, I have not yet tested them to their full extent, meaning, I'm not yet sure that they are truly better than some properly placed 100pf+10nf+friends.

Does anyone here have experience on them? This is a short-run, high-stakes, short deadline design, so the increased cost is not an issue.

Thanks!