| deskmate88 |
Hi,
It seems that the X2Y caps are the perfect solution for IC power supply decoupling.
From the tech spec, I am pretty sure a single X2Y cap will out perform any other caps for this function.
However, I am not sure how does the X2Y cap perform against some of the best parallel cap combination, for examples:
http://www.diyaudio.com/forums/show...44407#post44407
What's your take?
:smash: :smash: :smash: |
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| tiroth |
| What is "X2Y cap"? |
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| tiroth |
OK, I had a chance to read the literature. Although the X2Y caps seem to be most dramatically better in terms of radiated noise, they may also offer improvements in terms of decoupling. It looks like a large (~1uF) X2Y in the 1812 package retains the HF performance of a 100nF 0603 ceramic while having most if not all of the advantages of the larger cap.
I didn't see any tests of 1uF X2Y versus 1uF//100nF//10nF 0805 or 0612 ceramic, which would have been nice. My concern is that the difference is impressive, but not so dramatic that it is totally obvious to me that these will be significantly better.
You'll have to design the boards specifically for these caps due to the shield electrodes. |
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| tiroth |
| Note there is a spice model available too for those who might want to investigate. |
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| deskmate88 |
| quote: | | most dramatically better in terms of radiated noise |
What is the significance of this? |
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| tiroth |
It is very hard to say in the context of DIY. In general we are not concerned with acheiving regulatory-approval emissions levels, but that doesn't mean we are unconcerned about radiated noise corrupting our signal integrity or analog circuitry. That said, I think at the frequencies of interest in DIY DACs, decoupling is more important than controlling radiation by a significant factor. (provided appropriate rise time circuitry is used!)
I would like to see someone like Francios comment. AFAIK he is the only one to measure *and document* various digital decoupling schemes are our frequencies of interest. |
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