tiny dc/dc

That vertical relative to the PCB winding structure is really nice. Solved problems with clearances.

If only I could have a PCB manufactorer do that, but maybe it's out there.

Murata is 3.11mm PCB. Could be done with 2 1.6mm PCBs, and pocket milling, turned over, plopping in a ferrite, glue, and solder.

But, do they make the vias after the ferrite has been sandwiched?

Seems to me that they have to. It's an ordinary PCB fab process, except there's that ferrite inside the board first.

The vent hole on the side is interesting. Why not squirt in ferrite paste, or 3D print the core?

There are several people now who are integrating the isolation transformer into a single IC somehow.

I want a high power LED+solar cell IC, a really quiet dc/dc converter.

That can be done with the oxide layer, like for optos. The distance from the emitter to reciever LED is very small, but handled by the oxide layer that is approved for 20++ years lifetime for double insulation

AFAICR, the oxide layer is in the order of 10um, approved for +5kV isolation

For the icouplers, it means they can make a transformer with quite good coupling factor

Wont they get in trouble with conducted emissions, since only a very small parasitic capacitance from primary to secondary is able to push a lot of current at 64MHz?

Not if you double screen. A conducting screen on each side of the isolation barrier, grounded to its local ground, blocks electrostatic coupling. Of course the currents flowing in the screens produce some voltage drop and that does drive some current across the isolation barrier, but a whole lot less.

Ralph Morrison's 1960 book - "Grounding a Shielding Techniques in Instrumentation" has quite a lot on that, not that 64MHz came into it back then.

john larkin snipped-for-privacy@glen--canyon.com wrote: ...

But now out of stock everywhere...