Half Pepperoni, All Cheese
- Sep 15, 2015
- North Carolina, USA
Now this little info changes a lot.increased risk of burning or wearing out over time compared to MLCC. And they are usually bigger.
I would rather avoid the tantalum, too. Personally I do not have an issue with the noise whilst USB devices with large power draw are attached, as this is not going to be an often use case for me anyways...
How can we avoid?
This is where tantalum comes in as an option. But they have different drawbacks: increased risk of burning or wearing out over time compared to MLCC. And they are usually bigger.
- Use bigger sized ceramic capacitors which reduces the effect.
That does not apply to all tantalum caps, though. They actually have their origin in the military sector for their high durability, those older types using a fluid electrolyte do not suffer from these problems - they last forever without losing any capacity. It's too bad that the traditional axial format is not being manufactured anymore - I still have some of those, over 30 years old and still good to use. Those wet ones are fairly expensive, though.Now this little info changes a lot.
The way I read it is when talking about bigger ceramic caps, he was talking about their capacity in uF, but when referring to tantalum caps he was talking about their size in square millimeters. Now, significantly bigger ceramics are commonly found in bigger physically sized packages too, so either way it seems greater or lesser layout rework will be needed. Tantalum caps tend to be higher in electrical density, so would probably require simpler rework, but I'm slightly surprised you can't get tantalum caps in the same physical size as the cermaic one we were using, but perhaps the manufacturing process is more difficult to miniaturise to the same degree, as these SMT parts are often some kind of tiny.One option says "Use bigger ceramic", while the Tantalum option says them could be bigger
if everything is right here, seems to me that the obvious thing to do is using bigger ceramic capacitors
We have designed for ceramic capacitors ("MLCC") and there was only one manufacturer who build 100µF ceramic capacitors small enough to fit.
So we did take one 100µF and a 22µF in parallel on the previous board revision. This time I can experiment with different mixtures like 2 x 68µF.