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| PlainName:
--- Quote ---It's intuitive. --- End quote --- Is it? The DIL device scores by being able to have its legs bent over and soldered down on the other side of the board. That isn't going to come loose too easily. OTOH the SMD device is held on solely by the strength of the glue holding down the tiny pad. Levered with a screwdriver, as a test, I know which will come off first :) |
| Cerebus:
--- Quote from: dunkemhigh on December 30, 2021, 09:50:30 pm --- --- Quote ---It's intuitive. --- End quote --- Is it? The DIL device scores by being able to have its legs bent over and soldered down on the other side of the board. That isn't going to come loose too easily. OTOH the SMD device is held on solely by the strength of the glue holding down the tiny pad. Levered with a screwdriver, as a test, I know which will come off first :) --- End quote --- You might use glue, the rest of us use solder. This may also be a clue as to why you've been having difficulty getting SMD stuff to work. :) But seriously, brazing/soldering about 50% of the area of a very light part (~10mg for a DHVQFN16) to a board, as compared to suspending a heavier part (DIL16 1100mg) off the board on flexible metal legs it is intuitive which will be stronger, unless one has no mechanical intuition. Similarly the service loads on parts are a result of their mass being accelerated and decelerated, not some gorilla deliberately attacking them with a screwdriver. |
| PlainName:
--- Quote ---You might use glue, the rest of us use solder. --- End quote --- Ah, a bit too quick on the clever reply so you missed: --- Quote --- the strength of the glue holding down the tiny pad --- End quote --- Don't care how strong your soldered joint is if the pad lifts. This is why even SMD connectors often have either relatively huge mounting pads or hole for pins to be stick into. |
| tautech:
--- Quote from: dunkemhigh on December 30, 2021, 10:28:19 pm --- --- Quote ---You might use glue, the rest of us use solder. --- End quote --- Ah, a bit too quick on the clever reply so you missed: --- Quote --- the strength of the glue holding down the tiny pad --- End quote --- Don't care how strong your soldered joint is if the pad lifts. This is why even SMD connectors often have either relatively huge mounting pads or hole for pins to be stick into. --- End quote --- Consider those might also be for shifting heat. ;) Otherwise I'm with Cerebus, less mass in a high vibration environment has to be better provided the PCB is also restrained properly. |
| Cerebus:
--- Quote from: dunkemhigh on December 30, 2021, 10:28:19 pm --- --- Quote ---You might use glue, the rest of us use solder. --- End quote --- Ah, a bit too quick on the clever reply so you missed: --- Quote --- the strength of the glue holding down the tiny pad --- End quote --- Don't care how strong your soldered joint is if the pad lifts. This is why even SMD connectors often have either relatively huge mounting pads or hole for pins to be stick into. --- End quote --- Any arguments about the bonding of the foil to the substrate apply equally well to a through hole part but frankly that's irrelevant; all the mechanically failed through hole parts I've seen it's the actual leads that have broken, not pads. Both SMD and THT parts have adequate mechanical connection to keep them attached to the board except under extreme circumstances or deliberate attack. What the THT parts have that the SMD don't is a vibration failure mode that is much more important than whether the part can be ripped from the board or not. As I say, all the real life mechanical failures that I've seen have have been from that mode. Arguing about connectors when we were talking about chip parts is just doing a bait and switch. Connectors are always going to require relatively heavy mechanical connections to boards if they're board mounted, whether they are SMD or THT. The 34 way through hole connectors I've got on order have bolt holes on them for a reason, 3M aren't expecting the solder pins to provide an adequate mechanical connection on their own. |
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