Which PCB-mounted SMPS brands are good?

Astrodyne, I've never see a failure with their switchers.

Cheers

We've been very happy with MeanWell open-frame switchers. I don't know if they have PCB-mount stuff. PCB mount supplies take up a lot of board area and can cause a lot of vibration problems.

We're getting their LPP-150-48 (150 watt PFC switcher with input EMI filters) for $44.

Can you use an external wart?

John

Thanks, Martin, now I remember that brand. I think they sell directly and not via distributors. Looks like they only sell versions of open frames that must be screwed on:

BTW, while scoping out some supplies I realized that the Cincon 15W supplies and the Lambdas look quite the same. Hmm ...

Thanks, John. Mouser has one that looks like it is footprint-compatible to the Lambda and to the remarkably similar Cincon:

Where do you buy yours from?

Nope, has to go onto the board. The problem with bolt-down is the extra hassle and cost in assembly, plus bolts can come loose. Board space isn't really lost because the supplies ride one or two tenths above so you can place stuff underneath as long as it's not fat inductors.

PCB mount would be really nice if they had a few more dummy pins or at least positioned the pins in the four corners so you get less vibration. But for reasons that completely elude me they don't.

Powergate LLC. Jameco and Mouser also have them, but are more expensive.

John

Thanks. No prices on their web site but they've got the MeanWell NFM-15 series, so it's just a phone call. The vibration specs do not look good though. Dang, this thing would be almost ideal. Maybe we can spritz some goo underneath.

RTV the wiggly parts.

John

Well, the whole thing will be the wiggly part because it rides on four puny pins ;-)

Possibly squishing silicone under the four corners works.

I had a problem with PC mounted transformers and them tearing loose. When the device was dropped, the transformer would break loose and become a bowling ball inside the enclosure. I tried tie-wrapping the transformer down to the board but they still broke loose. I started using "Gorilla Glue", the kind that activates with water and foams up. 362 units later and not a single failure.

Ah, thanks, here comes the hardcore practical stuff :-)

Is it this one?

They also have an epoxy. What I'd need is something that retains a wee bit of flexibility because upon hard shocks the boards with, well, flex a bit versus each other.

Sounds good. Is there an adequate UL flammability rating on that stuff?

Serious double-stick foam tape might be good.

John

Yeah, like the kind that rock bands use to stick their cables onto concrete :-)

However, these supplies have stepped pins and there seems to be a large gap between SMPS board and circuit board. Around 2/10" or so. So it would have to be pretty thick foam tape. Plus it can't have as much compliance as, for example, weather stripping because then it wouldn't protect much against ripping the SMPS off during a fall.

It would have been so easy if they had just added half a dozen dummy pins for extra mechanical support. The alternative would be to reduce the gap substantially but that requires rework, prying the pins from the SMPS, replacing with shorter-stepped ones and thus voiding the warranty.

RS has traco power TMP 15112 (12V,15W) for ~30=80 in ones

pins are not quite in the corners for 15W, 30 watt is

it has threaded holes for two screws in the bottom

-Lasse

Thanks, Lasse, looks like a good one and John's supplier PowerGate has them:

If they sell those for around $20 in hundreds that would be nice but could be a stretch. In case anyone else needs this stuff here is the spec sheet with the mechanical details:

See if any of these 3M VHB tapes might do.

Thanks, Joe. Seems that they are a bit too thin but it's hard to get to tech data there. A classic example for the topic "How not to design a web site" :-)

Back in the old days I used Melcher (now Powerone) a lot.

I still do (their linear supplies). But AFAICT they don't have much AC/DC in terms of board mount, only chassis mount.