Transformer Surface Mount

Yes. Have you tried RSComponents? Maplin? Radio Shack? Farnell or anywhere that might sell them? Or do you want me to do the searching? No size constraints, then? Just the one or several? How many, then? Budget constraints? Commercial constraints - you're not in Cuba, are you?

Never worked with surface mounted transformer before, only the chunky one. Just wanted to ask if the surface mount can tolerate that much power. Guessing it's a yes Chill out with the sarcasm buddy. Wasn't necessary Thanks anyway :)

Thanks for the insight man :) Much appreciated!

In addition to Dell's insight, it is also unlikely that SMT equipment could pick and place such a heavy device.

Also, the device would need to run through the reflow oven and reach stable equilibrium temps for proper soldering. The necessary temp profile would probably roast most other components.

The temp profile and slow reflow speed would probably also need a special solder paste developed (Flux content specifically) and an inert atmosphere.

Then you would need the transformer to be able to withstand the temperature cycle itself.

You would also need a super smooth reflow chain, since the surface tension of the solder would not hold such an item in place on the board (Or else the device would need locating pins through the board).

Why not go for a SMT socket and a matched transformer that can be post fitted?

How about a transformer mounted using through hole technology?

I can't find one at 100VA that small enough to stand on a PCB.

We have built transformers larger than this. The transformer frame can be stud welded to the case to stress relieve the terminals. We have one transformer that weighs in at 250 lbs.Of course our surface mount substrate is a granite slab.

The answer is yes, but ...

SMT transformers are very popular, even for use at moderate power levels, but this is accomplished by performing the desired operation at high frequencies, e.g., 100kHz to 3MHz. In your case the designer would start with a PFC step-up converter to make say 380Vdc, using a PFC converter IC with switching MOSFET and an inductor. PFC means power-factor correction, which would make your load look resistive to the AC line. Next they'd use perhaps a half-bridge converter IC with a step-down transformer stage to create 28V at 3A.

Here's an SMT transformer with roughly the right rating. For my designs, I'd probably prefer to use a through-hole part of the same style and size.

Someone should add that the 1st step of a PFC step-up stage can be simply replaced by a bridge rectifier with bulk storage capacitors, certainly at up to the 50W level. The issue is of course, what has to operate at 60 or 120Hz? You don't want that to be magnetics. But something has to be large enough store the needed energy across the 60Hz sine-wave low-voltage and zero-crossing.

Pico Electronics makes 400 Hz surface mount transformers up to 50 VA. The larger ones have a threaded insert in the middle for a machine screw to provide holding strength.

http://www.picoelectronics.com/surface/pe018_mini.htm

the transformer from murr electronics comes with standard 24/26/28 v output and available current rating 2 , 2.5 ,3 ,3.5 ,5 and 10A

You did not include the working frequency? If it is 60 hertz, then the answer is NO!

A 100 watt capacity transformer is way too big and heavy to be surface mounted..

Yes there are.. and there are some that don't fit into your spec, however, if you go look at whats on the shelf at the suppliers, even RS have great online photo's I'm sure you could see one suitable for your application, and with a bit of know how, you'd make it work for you.

I use large Tx's all the time, and I have never had a issue with the fixings/mounting feet/brackets...never had one snap off, fall off or break free during transit.... I guess you'll have to see what does it for you.

ps.. as a newbie, you will have to get use to the less than helpful comments, it's what we do! Give as good as you get, the banter providing its clean and NOT insulting, really is welcomed and provides a little bit of light entertainment, BUT not at the expense of anyone's feels. However if you care to read some of the questions asked in the past, you will see why for many, a cull, would be the only answer.

Anyway.. welcome to CR4. I hope you enjoy this place... look forward to seeing more posts and hopefully, your quick fire wit!!

what is the purpose and where to use of @ 3A Surface Mount X-mer ???