ESR: How low is too low?

[momaka]

Re: ESR: How low is too low?

Nichicon NU in particular is not too expensive. And I think they may be more reliable, too?

Polymers will definitely outlast the useful life of the video card. If you can get them for cheap, just go with that. Nichicon/Fujitsu NU is good. You may also look into the R5 and R7 series - IIRC, those are even cheaper.

What forms of DC-DC regulation would be sensitive to too low ESR?

As far as I've seen, none really. Both linear and buck-type DC-DC cope fine with ultra low ESR. Lowering the capacitance too far may cause an issue, tough - particularly with linear regulators.

There is a general "half rule". It applies to modding buck-type VRM circuits with polymers. Bascially, use about half of the capacitance of the original electrolytic capacitors. You can use more than that or even the same as the originals, but it gets expensive. Overall, polymodding is experimental, but the half rule has been proven to work more often than not.

[Agent24]

Re: ESR: How low is too low?

There is a general "half rule". It applies to modding buck-type VRM circuits with polymers. Bascially, use about half of the capacitance of the original electrolytic capacitors. You can use more than that or even the same as the originals, but it gets expensive. Overall, polymodding is experimental, but the half rule has been proven to work more often than not.

I thought that came from a datasheet appnote and was specific only to certain VRM controllers, not a general rule for all of them?