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High frequency buck regulators and MLCC frequency behaviour
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thinkfat:

--- Quote from: OM222O on April 28, 2019, 02:17:17 pm ---the voltage controller itself won't be an issue  [emoji14] the poor mosfet that has to switch at that frequency will be.
you will require active cooling at 2.4MHz for sure ... unless you're drawing something like 100mA  :palm: as I said before it's switching loss, not conduction loss  :scared: he will realize it sooner or later

--- End quote ---
Hm, the LMR14030 I mentioned allows for roughly 90% efficiency, I run it at 1.6MHz or thereabouts, and at 15W out it will get to about 55 degC. On a rather small PCB. Of course the inductor and diode are external, that helps dissipating the heat.

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Ice-Tea:

--- Quote from: OM222O on April 28, 2019, 02:17:17 pm ---the voltage controller itself won't be an issue  :P the poor mosfet that has to switch at that frequency will be.
you will require active cooling at 2.4MHz for sure ... unless you're drawing something like 100mA  :palm: as I said before it's switching loss, not conduction loss  :scared: he will realize it sooner or later

--- End quote ---

If only devices would exist that have the FET(s) integrated or somesuch... In that case, parisitcs would be minimized, the FET would be well matched to the application etc. etc.

Oh, if only such devices would exist!
T3sl4co1l:
You say that, but I've seen integrated switch (regulator)s, of the synchronous switch type, that had just enough dead time, and apparently just the right doping profile, to exhibit drift step recovery behavior.  Sub-1ns pulses from a regulator, who'd have thought!

Indeed, it's frustrating that most regulators don't have separate drain pins, so you can't control the parasitics yourself.  You're forced to hard-bypass them, lest their control circuitry go crazy (or, so one would presume; alas, I've not actually tried, yet..).

On that note, though, the ones with internal LDO and external bypass pin, should be able to be snubbed, at least a little.

Tim
jbb:
On the ceramic capacitor front: as DC bias is applied, the capacitance drops. This could move the self resonant frequency up a bit.

On the integrated modules: they’re a bit hard to rework. When you apply heat and try to remove them all the subcomponents can come unstuck.
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