Murata 1W small isolated module

Den torsdag den 22. marts 2018 kl. 01.06.38 UTC+1 skrev Klaus Kragelund:

Den torsdag den 22. marts 2018 kl. 01.11.07 UTC+1 skrev Lasse Langwadt Christensen:

and this one,

I'm using muRata NXJ1S-series.

Just eye-balling, it looks like a two-transistor multivibrator driving a planar transformer, with a bridge and filter on the other end. There's a chunk of ferrite trapped inside that rattles.

Lasse's video from mikeselectricstuff shows that the pcb's built around a toroidal core, with traces and vias forming the windings. Slick.

Cheers, James Arthur

Mike Harrison used to post here, and had a lot of good things to say.

Hey, Mike, you still around?

Cheers

Phil Hobbs

I like the PDS1 types

which have a lot of single and dual-output variants, and are multi-sourced.

Those are pretty sweet. The muRata are tiny, though, and Ciso=2pF, so, perfect for floating supplies that have to fly.

Cheers, James

Nice :-)

Yes, and tested to 3kV. But probably need to be derated to 600V, etc., for long-term HV use.

He hangs out on eevblog sometimes as "mikeselectricstuff".

His reverse engineering videos are great, full of good product design ideas (whether it's of his own designs or others).

Yep, I suggested them to you for your pulser, way back, remember?

I think the NXJ1S are tested to 4.2kV... . Ah here it is: production tested to 4.2kV for 1s.

Slick little parts. Saved me having to roll my own.

Cheers, James Arthur

I'm a fan. He's a lot more listenable than the squeaky Antipodean, that's for sure.

Cheers

Phil Hobbs

I measured 16 pF on a dual-output PDS1. I have one use where there's an insane common-mode slew rate, so I added ferrite beads on the output side for some isolation. Hope that works.

The board is done; I should have the first built one to test on Monday. It's only expected to be about 25 v/ns or so. The beads in series with the output, 2.7K at 100 MHz, should help a lot.

A much larger CMC may be necessary. Data chokes may be enough, without adding too much diff mode impedance (which can be dealt with easily enough, anyway).

Tim

If there's 2.7K in series, I won't get 1.6 amps!

I guess I could sim that: two beads AC in parallel (there are bypass caps on both sides). One side slews 50 volts in maybe 2 ns. The other side has 16 pF to ground.

I need coffee and donuts first.

I didn't use a cmc because we don't have a suitable part in stock, and it seemed to me that two beads would work. We have lots of different beads in stock.

CMCs and RF baluns are usually not fully specified anyhow.

Oh, you're using resistors now? News to me... ;-)

I have a[n incomplete] saturable ferrite bead model. Even just starting with a saturable core model, will find interesting results.

Tim

No, they are 2.7K beads. I said that. That's 2.7K impedance at 100 MHz, the way ferrite beads are usually specified.

I don't take time to simulate it because it was intuitive to me that it would be OK.

With coffee and donuts comfortably stashed, it sims to a peak current of 75 mA per bead, lasting roughly 10 ns. I put pads on the board for an optional series RC as a ring damper, but it really doesn't need that.

What kind of beads are those? I measured a few and none even came close to 2.7k.

Jeroen Belleman