One of the most informative Electronics Engineering videos so far, this is gold info mate!!! =]
@EEVblog7 жыл бұрын
Thanks
@Mr_Wh17 жыл бұрын
I thought you like the display of POWER! ?
@TheHuesSciTech7 жыл бұрын
Excellent video! But at 24:18 the Open mode caps are the cheapest, not the most expensive. The 3 stars mean "excellent from a costing perspective", not "a lot of cost".
@EEVblog7 жыл бұрын
Oh, doh, that makes more sense!
@KillerSpud7 жыл бұрын
I've been working as a component engineer for a couple years now, so while I have seen this kind of stuff out there, it is nice for someone to put it all together. Interesting stuff.
@subigirlawd_73077 жыл бұрын
I've learned more in this 28 minute video then a year in school..thanks Dave..
@janijoeli7 жыл бұрын
This was amazingly fascinating!! Probably explains a lot of "I dropped it and it just stopped working" type of failures in modern electronics containing SMDs. Thanks for going through the trouble of doing so much research, and giving us the summary in a format of a well made youtube video. :)
@EEVblog7 жыл бұрын
Yep, could certainly be one of the reasons why stuff fails.
@KuraIthys7 жыл бұрын
Yeah... Might be. XD Though sometimes it's something else... (well, no duh. But anyway) After dropping it several dozen times my nokia 520, which had otherwise been one of the toughest phones I've ever had (barely even cosmetic damage even from drops on concrete and asphalt), finally gave up the ghost. So... I took it apart. (as you do). Initially couldn't find anything, but the way it worked intermittently led me to investigate the power... Sure enough, one of the 3 battery terminal prongs was loose. Broke the solder joint. Just shows what mechanical force can do. Surprisingly everything else seems intact. I guess the fact that the battery is a heavy, loose component might put extra strain on the connector... I'm sometimes surprised not just by what fails when dropped, but also what survives...
@janijoeli7 жыл бұрын
@Kuralthys, very true.. I should have said "explains a lot of drop failures which are NOT due to broken solder joints or traces", to be more clear. :) These three failures probably explain a very large percentage of drop failures. I just didn't know how fragile the ceramic SMD caps are, until now.... A good video.
@BenjaminEsposti6 жыл бұрын
I fixed my mother's wireless mouse which was dropped and had stopped working. The lovely lead-free solder on the crystal gave way, causing it to flap around in the breeze partially disconnected. Re-soldered and it has worked ever since.
@flymypg7 жыл бұрын
Splendid having all these hints, tips and tricks in one place! When putting boards through shake&bake testing and HALT, at one employer we often did a final test on our "sound stage", where we attached linear coil audio-band actuators to each mounting post, and activated them in combinations to induce all mounted vibration modes while monitoring for performance deviations due to MLC failures. Found so many issues for one product that we built a sound stage into the final production board test station, so boards were sound tested before any other tests. We used MLCs because of their otherwise great environmental ratings, especially radiation hardness and vacuum tolerance. They're amazing little wonders!
@EEVblog7 жыл бұрын
Brings back memories!
@johnfrancisdoe15637 жыл бұрын
BobC Space?
@flymypg7 жыл бұрын
No, it was for friggin' military vehicles. Worse than helicopters when it comes to shock and vibe. Most vendors surrender much of their volume and mass allotment on isolation mounts. Our MEs and EEs, together with our fab house, came up with a new strategy that's still a trade secret over a decade later. The MLCs were the "weakest link" in the system, but we couldn't get rid of them. Fortunately, boards that passed our testing had long lives in the field. But the in-house infant mortality rate was fierce until, one by one, many of the MLC tips and tricks Dave covered were finally incorporated. One trick we tried, that Dave didn't mention, was to put clusters of MLCs on a daughterboard sitting atop a high-density Hirose connector, with the assembly retained with nylon fasteners. It works mechanically and electrically, though the COGS hit is terrible, but possibly acceptable for military and extreme environment systems. It also works for one-off or low-rate boards, particularly prototype and debug boards with BGAs, where it can help get lots of decoupling caps in very close using larger MLC packages.
@PeregrineBF7 жыл бұрын
I remember several fellow EE & Comp E students complaining about having to take a basic mechanical engineering class. This video is a good example of one (out of many) reasons such classes are actually quite useful.
@ethanpoole34437 жыл бұрын
SAI Peregrinus A lot of cross discipline classes tend to be far more useful and transformative than they may at first appear to be. I was a CS major, years ago, and I would have to say my most transformative class was without a doubt a single class in anthropology -- which I took my very first semester, who would have guessed, but it fundamentally changed my perceptions of others and how I relate to other cultures and ideas. But it is always helpful to be exposed to other ideas and disciplines as they can transform how you perceive concepts and ideas as well as how to communicate them with others.
@johnbellas4907 жыл бұрын
Wow I never really realized or thought that these small SMD caps were so fragile in cracking like they are !!! and the many ways that you can design board layout to reduce the chance of a failure, as well as specify chips designed differently to avoid cracking failure !!! Real INTERESTING, THANKS DAVE !!!!!!
@EEVblog7 жыл бұрын
Glad you found it useful
@KuraIthys7 жыл бұрын
This truly is one of those things you don't learn from standard electronics design textbooks. Serious gotcha, so it's great to see some of this more obscure knowledge for us inexperienced hobbyist designers...
@Catoblepa777 жыл бұрын
Hi Dave, IC Test Development Engineer here. Probably the best video in the latest months, you clearly have lots of experience on PCB design and sharing it is very interesting and formative!
@nBoxes7 жыл бұрын
If only professors would teach with half of the enthusiasm and knowledge as Dave here I'd go back to school tomorrow.
@bepowerification7 жыл бұрын
you had professors at school? wow. here in europe we only have teachers. and at learning facilities where professors teach it doesnt make a big difference because people are going there because they WANT to learn.
@MetatronicModsLLC7 жыл бұрын
>>you had professors at school? we call all of it school in the US >> people are going there because they WANT to learn confirmed, definitely not from the US.
@RWoody19956 жыл бұрын
You can want to learn something with a passion and still fall asleep while learning it if the professor teaching it has zero enthusiasm for the subject themselves :/
@sandrucristian19833 жыл бұрын
I can't believe it, this is exactly the explanation we are looking for, now I know why the capacitors are failing, I just took out a capacitor that shortened my motherboard from my laptop
@george8bitsworth7 жыл бұрын
I think your best videos are the instructional ones. This certainly was one of those. Just a note, this started out as a failure (the magic smoke) but it led to a great learning exercise.
@Aerospace027 жыл бұрын
I'm a PCB Design Engineer in the automotive industry. Whenever MLCC's are on any circuit that's connected directly to battery, the capacitors must be in series. Also, the two caps have to be 90 degrees to each other. This is done with the thought that the board will typically only flex along one plane. Most auto companies don't seem to use those Megacaps very often because they're too expensive.
@Alexandru-Mihai7 жыл бұрын
Same here, I can agree to that. I would also add that fexible termination caps are widely used now, almost exclusively. In my experience the "megacaps" are a rarity and are only used in very dense designs where the smaller footprint size for the same capacity is more important than the higher price of these parts.
@truesoldier277 жыл бұрын
Awesome information. Not very often someone would run across this kind of issue and know why. Thanks for going into detail, very informative!
@Pi-Tutorials7 жыл бұрын
Stress = load / area , i.e. pressure. The correct term to use is probably Strain, which is change in length / original length. Nice video, thanks.
@photium92306 жыл бұрын
Thank You so much for this video. I recently made a electronics project, but it ended up having a dead short. I took off the SMD ceramic capacitor, and it works great!
@irgski2 жыл бұрын
Good video! As mentioned, this is learned in the school of “hard knocks” and (rarely) in any Uni. Had a memory card that was randomly causing the memory chips to “loose it”. Root caused it to microcracks in the mlcc decoupling caps.
@Daveyk0217 жыл бұрын
Excellent video/article. In my repair of the instruments I work on, shorted ceramic caps have been an issue, especially if a drop is suspect. In the old days of through hole, shorted ceramics was as rare as Jen’s teeth (although I’ve seen two in ~36 years of service). In surface mount, shorted ceramics seems rather common. Watch some of those iPhone repair videos (Jessup at iPad Rehab), and shorted ceramics in iPhone 6+ phones seem the most common failure. I fear dropping my phone now even surrounded with a genuine Outter Box case.
@lbek7 жыл бұрын
This finally explains the isolation slots around big mlcc caps that I see on some lcd panel controllers, tnx Dave!
@Sembazuru7 жыл бұрын
Back when I used to do component level repair on cell phones, our quick and dirty check for cracked ceramics was to touch the end-cap of the cap with our soldering iron. If the cap was cracked then the end of the cap will stay stuck to the soldering iron (due to surface tension of molten solder).
@EEVblog7 жыл бұрын
Yep, that can work a treat.
@loungelizard8367 жыл бұрын
Thank you for spending so much time on this in depth discussion of your crack!😈
@epremeaux7 жыл бұрын
Great timing as I have been struggling with a product I designed which has had a few failures like this on high voltage / high current supplies.
@joelbrown89726 жыл бұрын
Very interesting and helpful. As you might know, there is a global shortage of ceramic capacitors. We are constantly having to specify new P/Ns as the ones we are using become unavailable or obsolete. Using special technologies such as Megacap or soft termination may be a good solution to the cracking problem, but relying on a single vendor for a special technology in today's market environment just isn't practical at least for us. I think the best mitigation for us is controlling placement of caps in the layout, using smaller size caps or using non ceramic caps where it makes sense.
@jotaemebee7 жыл бұрын
Dude, this is a ridiculously useful info when designing the pcb layout... thank you so much!
@EEVblog7 жыл бұрын
No worries.
@AdamPaul-e5y21 күн бұрын
One thing that is worth noting is that even cracks that do not directly short the inner plates together. They can expose the internals of the MLCC to air and contamination, allowing for internal ECM (Electrochemical Migration) growth, which will lead to similar failures.
@bbreeuwer45777 жыл бұрын
Great video, even for pros who have been in the field for many years!
@MaxintRD7 жыл бұрын
Great follow-up of you previous video. You answered all remaining questions I had. Thanks!
@EEVblog7 жыл бұрын
Beauty.
@baspro757 жыл бұрын
Thanks for the invaluable information you present, Dave!
@flomojo2u7 жыл бұрын
Very informative, thanks Dave! I also really like the new graphics you're using at the start/end of your videos, very modern looking.
@JamesDoebbler7 жыл бұрын
Excellent info, thanks!
@guillep2k7 жыл бұрын
This is the kind of videos I reeaaaally like. Thanks, David!
@TomWalterTX6 жыл бұрын
Great Video. First time I came across mechanical stress into a package was with a Switched Capacitor Filter. MF10 around 1984.
@crayzeape22307 жыл бұрын
A standard MLCC that has 'failed open', has a high possibility of becoming 'failed short' over time due to shock/vibration. So, is 'failed open' really a valid failure mode in this case. There is probably a case for 'failed working', where the layers on each side of the crack still line up and make contact, just waiting for the next bump before deciding whether or not to burn the house down.
@CNe75322946 жыл бұрын
Thank you for this Dave. We need more awareness on things like this. It is my hope that soft terminations or something even more impressive becomes the gold standard. Sure demand gets driven up immediately and along with that comes price. However, just like side airbags and ABS we may see this in such high demand that output will try to match up to it. In other words, it should become cheaper in the long run. After all, who wants a product that can catch on fire.
@bart4167 жыл бұрын
Since I didn't see it in the video while skimming through it: A trick we often use with flex circuits is to make cuts around the component in strategic locations to prevent the substrate from bending there. For example you make a U shaped cut around an island where you place a few passive components. It'd be interesting to see a series on flex circuit design actually, especially given the low price for flex in China these days.
@fuzzy1dk7 жыл бұрын
next up tantalum capacitors? voltage spikes, current spikes etc. and you get thermal runaway and an explosion
@yoshmarklund7 жыл бұрын
Really like this little mini-series :)
@VTHTECH7 жыл бұрын
Lol, same here
@CarlsTechShed7 жыл бұрын
Hi Dave. Have you considered making a video showing examples of really bad PCB layout and design?
@jeffreyt9917 жыл бұрын
That could actually be very educational.
@aneeshprasobhan7 жыл бұрын
he already has
@SeanHodgins7 жыл бұрын
He does, its called Mailbag. haha, I joke. I hope something of mine will show up there soon.
@esdblog61007 жыл бұрын
It is easier to talk about good pcb layout practices than wrong. Ask not electronic fellow of yours to route your PCB and you can easily make a video how bad PCB design can be made.
@PETMK7 жыл бұрын
There's a lot of details you have to know. Yesterday I had finished PCB that takes me six days - and it is not from the scratch. Can you imagine I have it on video and after each of trace tell "Now it,s better to put this signal to layer 3 as in layer 2 is the local ground plate to shield the oscillator"? I think show fails and it's results is more interesting...
@markushahnenkamm6 жыл бұрын
Learned this 1 Year ago at university Very interesting, that i learned something that coveres real world Problems
@TerranVisitor3 жыл бұрын
High value video. Thanks Dave!
@maelgugi6 жыл бұрын
So much I didn't know, so little time. I do now comprehend Fausto.
@abisaiamatalo27692 жыл бұрын
Awesome video. Watching all the way from Kenya.
@truemorpheus7 жыл бұрын
I find this really useful! I would love more stuff like this in the future
@czorgormez6 жыл бұрын
great informative video ! one another possible crack cause is wrong setup in pick and place machine. normaly a pnp machine needs to know component height. many operators doesn't care or bother to check different caps for heights. they just use simple template for 0603, 0805 etc. but in reality 100nf/0603 and 1 uf/0603 caps are in different height. so if pnp machine pushes a little bit much that cap to the pcb. that can cause stress cracks or become more sensitive for future stresses on the pcb.
@ZylonFPV7 жыл бұрын
“Please excuse the crudity the model, didn’t have time to build it to scale or paint it” Reminds me of Dr Emmett Brown 🤔
@Daveyk0217 жыл бұрын
Lol
@maelgugi6 жыл бұрын
Be aware, he might have a flux capacitor as well. I hope so.
@ilanmagen7 жыл бұрын
Thank you for this deep cover of the subject
@sangeeth_6197 жыл бұрын
This is an excellent reference video! I reckon you should also make similar video about all sort of capacitors and other SMD components.
@MicraHakkinen7 жыл бұрын
I suppose you could also increase the pcb thickness to reduce flexing. Of course like all other options this too has its downsides, but it may be worth considering in some circumstances.
@tom76017 жыл бұрын
I've got an idea! Put wire pigtails on both poles of the caps then solder the pigtails to the pads. Maybe I can patent the idea! :-)
@alexdavis97946 жыл бұрын
Hey Dave, you mention changing output voltage from references due to board stress, but it's also worth noting that things like op amp offset voltage can be affected as well. In most general-purpose cases, this isn't too much of an issue, but in very high precision applications, it can be a big deal, especially if you get board flex due to thermals. Good video, and very informative!
@Mehrad8barheM7 жыл бұрын
Actually Digi-Key sent me a catalogue item while ago about Samsung soft termination MLCC caps and when I've seen your video about that power supply catching fire I was thinking of letting you know about them. You have firgured it out yourself obviously. Cheers
@ElectraFlarefire7 жыл бұрын
Your really getting your value for money out of these modules. :) I'm not complaining mind you.
@Arek_R.7 жыл бұрын
Now I will be worried about every capacitor...
@richardsandwell22856 жыл бұрын
We lost something when we moved away from all through-hole mounted components.
@noahhastings61454 жыл бұрын
@@richardsandwell2285 Yes. We lost a lot of wasted space. And our houses because they burned down
@MichaeltheCrank7 жыл бұрын
This is really good to know. Thanks! Dave.
@PileOfEmptyTapes7 жыл бұрын
What may be worth mentioning is that shorting tends to be caused by silver migration through the cracks under voltage. Clearly, SMT MLCC + lead-free solder is a somewhat... _explosive_ ... combination.
@BerndFelsche7 жыл бұрын
My rule of thumb: Choose the automotive-qualified parameter if available in parametric search when all the other technical parameters are given. Even one-off toys then have a better chance of working.
@alimoradi23233 жыл бұрын
I never thought this would get so much critical
7 жыл бұрын
As a design engineer, one very common failure I see on SMT capacitors is mechanical contact (hits). People handle large board assemblies carelessly and hit them to objects and to each other. I see a lot of cracked capacitors on the board perimiter, as they are more vulnerable to being hit.
@UOTCbassist7 жыл бұрын
Damn, do they seriously not teach this stuff in school? I have no formal education in electronics, everything I know is self-taught on the internet, but it seems like this stuff should be taught in schools. Kinda basic stuff that can greatly improve reliability in electronics.
@RWoody19956 жыл бұрын
Nope. most people get to their final year before they realise you need a ground reference as well as Rx and Tx connections between one device and another on a floating power supply :/ EDIT: "most" may be a biiiit of an exaggeration, I exaggerate too much :p
@UOTCbassist6 жыл бұрын
No kidding, that's pretty nutty! I guess it's the same with pretty much any kind of formal education. They just teach you what they "need" to teach you.
@gigavolt61766 жыл бұрын
Hi Dave, Great video. At 24:24 you mention that the 3 stars mean the most expensive. The stars are from an engineer's perspective and are meant to represent lowest cost.
@zokonjazokonja7 жыл бұрын
I would like to add additional info about this topic, SMD capacitors should not be soldered with hot iron because it can cause thermal cracks inside ceramic structure because of rapid temperature change. Best way is to use reflow oven if you have it, next option is hot air soldering, worst option is hot iron. I think that some SMD MLCC producers highlight this, I know that Epcos did.
@rolandosalgado15527 жыл бұрын
Great video, very common failure in laptops, !!!!!
@Fir3Chi3f7 жыл бұрын
I might never find this useful, I did find it interesting though! Thanks Dave!
@thesailormen7 жыл бұрын
I had a similar problem a few years back. The burn glass fiber was conductive and red when power apply. i used a alumina sand blast (pen style sandblaster) to remove all the burn area and fill the hole with regular epoxy i even place back the pad on top of the epoxy and solder the capacitor on the pad. The equipment is still working.
@JulianIlett7 жыл бұрын
Bring back through-hole technology ;)
@BenjaminEsposti6 жыл бұрын
One way of reducing mechanical stress is by mounting the capacitor perpendicular to the likely bending forces as Dave showed, that way the bending force is more on the pads than the capacitor itself. Also good design practices suggest adding more mounting points if you have heavy components on a PCB. Also you can get MLCCs in a reversed connection, where the long sides are where the pads are. These are also good for extremely low ESR and inductance. One big trap is also the voltage rating of MLCCs. Some dielectric materials can cause dramatic drops in capacitance dependent on voltage. Also, I don't like those MLCCs with metal wings on them, they are so expensive! I suppose if I was making something for high reliability, it would be worth it. But in a regular consumer product, not so much.
@Darieee7 жыл бұрын
Awesome video ! Love these informative ones
@Alesij7 жыл бұрын
Very good video! Please, keep this content comming! :)
@uwepolifka45837 жыл бұрын
Thermal expansion was my first idea. If a brittle Cerco is mounted direct between two solid Output terminals and the solder cools down it shrinks again and it could pull the capacitor apart. I have the same power supply and I will remove the cap before it burns.
@over2seeyer7 жыл бұрын
This is brilliant !
@thekaduu7 жыл бұрын
Thanks Dave. One does not get this from schooling indeed.
@Soundfactory247 жыл бұрын
we had big problems with Murata's SMD multicap capacitors. Very often they are broken when the device has fallen off. The manufacturer has then installed again individual capacitors in the device
@AD-ng4mz6 жыл бұрын
In depth. Thank you.
@fay2137 жыл бұрын
very informative video, thanks
@Spector_NS5_RD7 жыл бұрын
"moldy layer ceramic capacitor" ~ Dave Jones ~ 2017
@userPrehistoricman7 жыл бұрын
I suppose that once they crack, mould can grow and create a problem.
@GRBtutorials7 жыл бұрын
Actually, I think the mould solves the problem. That's another technique, a secret one that Dave told us in an unsuspicious way.
@threepointonefour6077 жыл бұрын
“Moldymeter” -Great Scott
@MetatronicModsLLC7 жыл бұрын
I wonder if board flex from dip soldering processes was ever a problem for ceramics. I was really surprised when I visited a local manufacturer by how much a populated PCB will warp as it's dipped into the solder bath.
@hrnekbezucha6 жыл бұрын
I really like the new intro overlay.
@peepopalaber7 жыл бұрын
I did not understand much. But enough, that i checked the caps in my cars electronic box, because i thought it may be a problem with the vibration and/or flexing of the board and the caps broke ... and it was exactly that. thanks! Now it was not a 600 € repair, it was a ~1€ repair :3
@EEVblog7 жыл бұрын
Nice!
@juggernautforce7 жыл бұрын
I had an MLCC that failed once. It was used as an output cap. for an LDO. At first I didn't know what was causing the problem to my D.U.T., the power supply limit indicator kept blinking red and I thought the low-side ESD diode was shorting the output to GND. But when I replaced the output cap. of the LDO, everything was hunky-dory again. Turns out the output cap. which failed as a short circuit was causing the unwanted pull-down of the output of the LDO to GND.
@CATA200347 жыл бұрын
For the voltage REF, the cut-out is for thermal stalility, the bandgap might have heating element near it for improved stability, and the cutout is needed to beter thermal isolation,...not mechanical stress
@onjofilms7 жыл бұрын
The way we find the cracked ones is hot air flow them and push them around with an exacto knife. If the ends move separately, it's cracked.
@moth.monster7 жыл бұрын
Remember kids, if it's in two pieces it's cracked
@gorillaau7 жыл бұрын
If you can see light through it, the component is probably cracked.
@kennethgaler25977 жыл бұрын
Awesome video !!!
@leocomerford6 жыл бұрын
16:02 Apparently the somewhat ropey and by now quite aged capacitor you find connected between live and neutral in old valve amplifiers is affectionately known as the "death capacitor".
@ServiceComputers7 жыл бұрын
Brilliant!!
@diego.alienigena2 жыл бұрын
excellent video, very interesting as always 😀
@PeregrineBF7 жыл бұрын
You can also put a fuse (or fusable resistor) in series with the cap. That can be a cheap way to provide protection when you need a large MLCC (for low ESR/ESL with high capacitance or such). Film and electrolytic caps tend to have higher ESR, which can lead to thermal runaway in some cases.
@userPrehistoricman7 жыл бұрын
Wouldn't the fuse be quite detrimental for ESR and ESL?
@ethanpoole34437 жыл бұрын
Prehistoricman They certainly tend to be. They do make internally fused tantalum capacitors, though they may be fused more by the buildup of heat in a failing tantalum such that they disconnect internally before combusting. Though in some filter applications some added resistance or inductance could be used as part of the filter design.
@cibodor7 жыл бұрын
Very interesting video. But I'd like to note that tht devices almost don't suffer from this issue, even the cheapest ones in which the leads are too thin. Tht devices are also visually identified easily. The board that burned on you was probably hybrid smd/tht already if it was a power supply.
@avejst7 жыл бұрын
Thanks for sharing. Interesting stuff 👍😀
@asmi067 жыл бұрын
Great video overall, but I think the choice of 0402 size as example at the end was not the best idea, as to get significant bend over 1 mm of length (lateral size of 0402 is 1 mm) you need to apply a serious force which would probably cause some damage within the board itself too, not to mention that it will surely crack any leadless parts (the likes of QFN or BGAs) so at that point the board will probably be destroyed beyond repair. But this also proves that any board needs to have a fuse next to it's connection to the power source (be it power jack, USB port or whatever else) as a simple fail-safe in case some kind of short does occur. Luckily low-current SMD fuses are fairly cheap, so it shouldn't be a big cost factor. Also it would be a fun experiment to solder MLCC caps of various sizes on test boards and try bending the board to see what happens :)
@Lunas25256 жыл бұрын
Move them to a point not under such stresses or use a ceramic disc cap vs smd cap for that spot... put extra support for the terminals or put the terminals on a lead not attached to the board...
@hendrikoex11787 жыл бұрын
great channel, great man.......
@mcconkeyb7 жыл бұрын
Nice video!
@szoszaty7 жыл бұрын
"I woffled on long enough about... cracks" LOL
@BerndFelsche7 жыл бұрын
Structural hint: If you need a connector on the board, consider a straddle-mount on the edge. The spacing and length of pins of some through-hole connectors are amenable to straddle mounting onto surface-mount PCBs. [ Don't expect automagic assembly machinery to cope with soldering the connector.] Twisting of the connector can still impose stressses. Structural trickery by milling slots is to have only narrow bridges for traces between any connectors and the other components on the PCB. The strain (deflection) of the PCB is isolated as the narrow bridges are more flexible and will stretch accordingly with the more rigid part of the PCB on the other side of the bridge. Keep in mind that that extra flexibility means more flexing; which can be an issue in applications subjected to vibration. Some connectors such as Molex's MX123 series convey the intent to (rigidly) support the board *only* by the connector'pins, with the connector housing rigidly connected to the housing. Any strain at the connector due to the harness being (dis)connected or moving otherwise is thus largely contained. The tiny residual strain produces only a small movement of the attached PCB. Environments subject to vibration or shock still require some stress and strain analysis due to the inertia of the PCB and the components soldered onto the board. A thicker PCB substrate can save your bacon.
@antigen47 жыл бұрын
makes me wonder if the longevity of SMD products is going to lead to a giant crisis in a few years!
@BerndFelsche7 жыл бұрын
More to the point; lead-free solder apocalypse just around the corner.
@ericwrenfrow83496 жыл бұрын
That would be a transverse stress/load you have to worry about as opposed to a longitudinal. Transverse is usually the one you have to worry about.
@gblargg7 жыл бұрын
When life gives you lemons, you make lemonade. This is how you take failures and make them a useful occasion.
@blightgb7 жыл бұрын
Have you seen these same failure modes from tantalum caps? What is your take on the tan caps historical cracking issues (usually through mass reflow) and their impact in a high rel environment? Many of the major suppliers have run life tests that seem to point towards these cracks being insignificant, however some of the destructive analyses we've done shows the cracks propagating to the inner slugs, even prior to mass reflow.
@JohnDoe-el5ir4 күн бұрын
Decreasing pad size improves durability from cracks as well. Such capacitors get leakage current as well. I’m investigating a problem with 220u caps that get leakage usually of tens of uA up to few mA. Who is responsible that’s a good question. For now production is continuing without them.
@dhpbear27 жыл бұрын
I would mount it using 2 very short 'sky-wires'. Ah, I see at 17:55: Lead Frames!