SMD RJ45 vs Leaded RJ45

Apr 03, 2018 6 Replies

Hi



I am tempted to use SMD RJ45 to give me required space for more components instead of a leaded RJ45, which occupies a lot of space on the other side of the PCB also



But, cables, when inserted into the RJ45 excerts forces on the connector, and could pull a SMD type off the board



Anyone know of a SMD RJ45, which comes close to the stability of a leaded type?



Cheers



Klaus


People can step on the cable or drop things on it the wrong way. This can put a lot of stress on the connector.

I plan to use a bulkhead connector to take the strain, then a SMD on the pcb.

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I plan to leave plenty of room on the pcb for future development. I do not believe in cramming a small pcb with so many components.

I've used them in consumer electronics ( Thro hole plasic ones) with poor results! The fix was to use metal cased ones that have a metal tag that are 100% relaible. I presume you can get those in SM flavour.Even so, I would re bend the tags and make them throuh hole for 100% mechanical stability. I've seen professional setups using SM RJ45s and yes, they can get ripped of the board, complete with pads and tracks.If you go that route, consider vias in the pads to facilitate repair, not that that will help much if the whole thing is ripped off.... You could also consider bonding the RJ45 base to the PCB with epoxy but that may be too dificult to implement in your particular manufacturing environment.....It can be done....

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As others have said, not a good idea. We tried this on one product and it was a complete failure. The connector was being ripped off the board taking the pads and traces with it. We tried various fixes, epoxy to the board, epoxy to the case. They kind of worked but in the long run it was more expense than using TH and making the board a wee bit larger.

I have used them for connections inside a chassis. These work OK as long as you take vibration into account and secure the cable.

Chisolm Republic of Texas

How about one with mounting tabs (TH pins or pegs) and SMT connections?

Or there's truly heroic efforts in the name of size...

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(Strikes me as even more fragile than SMT alone, though...)

Tim

-- Seven Transistor Labs, LLC Electrical Engineering Consultation and Contract Design Website:

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We use SMT RJs that squeeze into a square hole in a metal end plate. That takes the big lateral forces. No problems.

Most such connectors have metal tabs that solder into thru-holes on the board, which will take the force. I'd be wary of ones that have only surface-mount pads.

John Larkin Highland Technology, Inc trk jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

s instead of a leaded RJ45, which occupies a lot of space on the other side of the PCB also

and could pull a SMD type off the board

type?

To answer your question, no. I have experience with other surface mount (S M) connectors which popped off the board because of repeated stress on the solder joints. One was a 40 pin IDE connector. Others are smaller connect ors with few pins, but with tabs for securing the device to the board. Sur face mount solder joints will eventually fail if the device is used much. Even if the pins are SM, if there will be much strain on the connector, my advice is to make sure the connector has mounting pins that are soldered as through hole.

Rick C.

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