That's just the problem, you can get out of one pickle just to be hit by the next one. I don't like things that cannot easily be inspected.
"Solder Honey", that's a cool name. When I was a kid we had a Burklin close buy (in Duesseldorf) but back then they would only let "professionals" in. Like radio and TV repair guys. So we occasionally borrowed a white coat and walked in to buy a flyback transformer that we couldn't find anywhere else.
-- Regards, Joerg http://www.analogconsultants.com/
In aerospace that's often done but here it would be a tad much. A non-BGA processor should give us all the reliability we want.
The customers will be hospitals and they turn around every dime these days. The times where the sky was the limit in medical devices are definitely over.
-- Regards, Joerg http://www.analogconsultants.com/
No space, plus it would not be allowed in this environment.
It probably could be. But why go through all this trouble and limited lifetime of such batteries when a clean uC solution affords us a bullet-proof power cut handling?
I just have to find local programming folks. But even with an OS it would be the same, just other guys.
[...]-- Regards, Joerg http://www.analogconsultants.com/
We are doing FFTs and some other stuff that goes beyond what a normal uC can do (but some ARM varieties can).
We really don't need that level of backup. But with BGA it can eventually fail as well as soon as the 2nd processor suffers loose balls and stuff.
Maybe, if there is a decent processor for that.
Yep. either that or use a uC that doesn't guzzle power to begin with.
-- Regards, Joerg http://www.analogconsultants.com/
Yes, overlapping FFTs. Buffering needs to be determined but it's not a problem because only a few bins must be kept, the rest is discarded most of the time. The other bins are only looked at in case of a disturbance and then the performance could sag for a second or two.
No imaging, this is all methematically digested down to a series of numbers.
Anything that can live inside a totally non-vented (as in sealed) box the size of three cigarette packs is fine.
That would work.
-- Regards, Joerg http://www.analogconsultants.com/
Oh come on, you will not be manufacturing in mobile phone quantities so that baking a tray of BGAs with some flux for 5-10 minutes will be a problem. I can tell you that on my boards with BGAs I have had soldering issues almost exclusively with the non-BGA parts. I did have a problem once under a BGA but it was the PCB manufacturers fault (had not drilled a hole they had to), now that was "fun" to fix. The worst offender by a huge margin is the qfn pakage (I use an Ethernet PHY in it). It almost always needs rework and the rework usually takes a number of attempts, I only recently invented a technique to get at least the rework right (a slight push with the tweezers on top of the qfn while liquid, not at all easy to do as it always wants to slide some places rather than just stick but I seem to have learned to do this, too (I am careful not to be saying too much though)).
I remember that shop, too (used to live & work in Cologne 88-92). But they closed it some years ago, only the Munich "Niederlassung" exists now (and they moved 2-3 years ago to a new address). But they are OK and since Bulgaria is in the EU shopping works normally, shipping charges well below 10 euro, 2-3 days delivery etc. You have ***no idea*** what a nightmare it used to be to get a package through the customs here, then Buerklin knew we had few other options here and I can remember paying 200 DM "handling" charges on a 1000 DM order.... Now there is also Farnell, some others less well known, we have even Mouser - they do process their shipments from the US through some point in Germany and things work door to door, too. Digikey are not that far yet, the customs nightmare is still on with them.
Dimiter
------------------------------------------------------ Dimiter Popoff, TGI
------------------------------------------------------
m).
rs.
eI think we can do this with the Atom and ECP3 as PCIe bridge and memory con troller. Lots of expansion boards are available with PCIe. Lattice's ECP3 is the cheapest FPGA with PCIe transceiver. It also come with 8 36x36 and /or 24 18x18 hardware multiplers, they would be handy in speeding up the FF Ts. Might need the ECP3-35 ($70) for more I/Os.
Intel Atom Z530 1.6GHz $30 Lattice ECP3-17 LFE3-17EA $25 Micron Sdram MT42L256M32 256Mx32 $14 Micron Nand MT29C8G96 128Mx32 $11 Audio Codec $10
--------------------------------------- Major parts $90
If you can commit to 1K pcs, we can build them for $200 ea.
You are worrying about problems that have been solved, and are handled fine by production companies with experience and knowledge in these things. If you are making your boards in your own basement, then it makes sense to worry about the production and solder quality. But if you go to a /good/ production facility, they will solder your BGA's correctly every time, and inspect them with X-Ray. If you need them potted, they will pot them with suitable material - including types with matching thermal expansion if your card is to be used over a wide temperature range.
People drop their mobiles all the time. I don't think it is much exaggeration to say that it is /never/ the BGA soldering that fails first. Every modern car has dozens, and probably hundreds, of large BGAs - many mounted in places with wide temperature swings and high vibration.
Now, it may be that you have particular reason for designing and producing the cards in a particular company (maybe your own company's production facilities), and that those facilities are not able to handle BGA's reliably. That's fair enough, and it's your choice - /you/ get to balance the pros and cons of different solutions. Just be aware /why/ you are limiting your choices, and that other people use them without problems. (Though I certainly admit they were scary at first.)
BGA production is not a problem, but prototyping is a bit more difficult. We usually need 8 to 12 layers PCB and it takes time and money to make. Al so, we usually need to have good relationship with the factory managers. I t's hard to ask them to do a few BGA PCB officially, just to deal with the paper work. However, with a few dinners and massage treatments, they can a lways do it for free. Physical gifts are NO NO.
We are not planning on assembling this in someone's basement.
Unfortunately they fail all the time just like they do on game consoles and laptops. A typical case reads like this:
Quote "I just got my phone back from a Samsung repair center and it appears the problem was a hardware issue. The service slip says it was a "BGA FAILURE" and they "REPLACED PBA"".
And they also fail by the droves. When they do it's always a four-digit repair bill and a usually long wait. Now you know why I drive a 17 year old Mitsubishi SUV with the least amount of electronics I could buy back then :-)
There is some technology that simply does not appear sound to me and BGA is one of them. Mounting a rigid component on a board that by its very nature is able to flex is IMHO not a good idea. Myriad failures and scores of re-balling and BGA repair services that popped out of the woodwork prove that point. If it's a very small BGA, DFN or other leadless chip that's ok. But not the big old fat ones.
-- Regards, Joerg http://www.analogconsultants.com/
My experience (with other people's designs) is pretty much the opposite. Assuming a top notch assembly process.
Most socialist countries and a few in Asia are worse. One engineer in India told me that it can take a serious bribe to "clear" a shipment and he has to drive a few hundred kilometers. That will keep a whole country back in terms of engineering if people can't get parts.
This is something I really like in America, you can order parts from Digikey and have them by the next morning before 10:00am. I think Mouser even does same day for folks in Texas, which is where things are now moving to anyhow.
Hmm, the Germans I know are mostly happy with Digikey as well and that should be in the same customs zone now as Bulgaria. Sometimes it's held up in customs but not just shipments from there.
-- Regards, Joerg http://www.analogconsultants.com/
Unfortunately, big chips with lot of balls are the reason for BGA If you r eally need the reliabilities, we can die bound the raw die. But the setup is quite involved and does not make sense for less than 1K pcs. Count on at lease $50K purchase of raw die, or the supplier won't even talk to us.
The first four line items would shrink to under $15 with ARM-Cortex though :-)
That could be ok in this case. The advantage is that we can base this on a more popular OS instead of a from-scratch C coding where the programmer would need to know the particular uC series. Which will hopefully result in more local programmers to be found.
Anyhow, if you are a consultant or run a turn-key house could you send me some details or a link to your business? Both the email behind my tag line link and the "Reply-to" work.
-- Regards, Joerg http://www.analogconsultants.com/
That sounds very strange to me - I would have thought that the cost of replacing a BGA on a phone is likely to be more than the cost of replacing the whole board.
I don't have any real-life statistics at hand. Given the gazillions of mobiles that are made, I certainly expect /some/ BGA failures - but I would expect other sorts of loose connections, screen problems, connector problems, etc., to far outweigh the BGA issues. I don't mean to imply that BGA's never fail - merely that when used correctly (good design and good manufacturing), they are not a major cause of failure in most systems.
Our Toyota must be that old - it doesn't even have central locking or electric windows.
However, I mostly trust the electronics in cars - it's the software that makes me nervous.
There are plenty of things you can do wrong with a BGA. And if you are using expensive parts, re-balling and re-work are worth the effort.
But unless you have a thin board that is under a great deal of stress, I don't see flexing as being a high risk. Modern small BGA's will be lower risk than big packages, of course, and you can reduce the risk with small boards, good mounting screws, etc.
All in all, BGA's are usually considered lower risk than alternative packages with large numbers of pins - by the time you get more than about 200 pins in a QFP you have large packages and very close spacing.
Hmmm, 8 to 12 layers? Not sure what boards you make but you may be well advised to look for some good PCB designer.
Here are a few of ours:
All in 6 layers, S-G-P-P-G-S stackup , 4 mil . The latest price we got for the prototype of the one from the first link on the above list cost us
Prototyping with BGA requires a factory that is able to handle them in small quantities - and things like temperature profiling takes time (and therefore money) regardless of the quantities. My company is happy with BGAs on prototypes, without any sort of gifts (but I can't tell you anything about the prices).
We have had cards with BGA's with 4 layers - sometimes 8 to 12 layers are useful, but they are not needed just because you have a BGA. If you have multiple fine-pitch BGAs then you will need microvias and many layers to get things routed, but many cards can be done with 4 or 6 layers.
For a 32 bits bus, there are 32 data and 32 address bits from the CPU, 15 to 20 address bits a 32 data bits from the SDRAM, 32 address bits and 16 data bits from the Nand flash. Most of these are going to the FPGA. Can't do it with less than 8 layers.
Forget about 64 bits bus.
In this case it's not so bad. The sound chip will go in serially so only few pins are needed. The same is true for the output which also goes through a DAC arrangement plus possibly another sound chip (need it down to DC there). So a 100-QFP would already be pure luxury in terms of IO.
Raw die is too expensive here.
-- Regards, Joerg http://www.analogconsultants.com/
Can't do it like it is done in the 6 layer boards I posted in my earlier message? Well, we all have a choice on the reality we think we live in (if not exactly on the one we do live in :-) ). The photos again:
Like on the one with the 3 BGAs I posted, its RAM is 64 bits wide - again in 6 layers, like all the rest (
Dimiter
------------------------------------------------------ Dimiter Popoff, TGI
------------------------------------------------------
They replaced the "PBA" which usually means printed board assembly. But the reason was a BGA failure. Aside from the cost that is also environmentally not good because small boards are often just tossed instead of repaired.
Well, I have seen too mnay in my life. Same with general electronics in cars that failed so often that I refuse to buy one with a gazillion uC in there.
Same with mine. Good old cranks and mechancical locks. Because I explicitly asked for that at the dealer. The sales guy did shake his head though. But the car then never saw the shop except for routine stuff like timing belts.
Also the hardware. I have seen some examples that made my neck hair stand up. The result is this:
Quote "When you look at the problems these vehicles have, they are mainly electrical or electronic issues".
People (like me) base serious purchasing decisions on this.
We do not want to have to compromise or have an expensive chassis just because of the BGA. It has to be very flex-tolerant because in the field it'll be dropped, strapped, torqued, rolled over, stepped upon and whatnot.
True. That's why I try to be content with 100 pins. In this case it is absolutely no problem because IO is serial.
-- Regards, Joerg http://www.analogconsultants.com/
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.