Motherboard Design Process

MBRFan writes "MBReview has posted the latest revision of their 'Motherboards - The Designing Process' article. This article covers the design process for modern motherboards, and also goes over some of the most common components that can be found. Definite read for information lovers, though beware, it'll take a while to read!"

Maybe someday they could get it right.

[Anonymous Coward]

Seems to be something which I dream of.

Wrong placement of capacitors and stupid placement of ports.

It would have been interesting

[antifoidulus]

if they also gave a little insight into what goes into the manufacturing process as well. After all, you can design the best board there is, but if you have trouble making it in large quantities, it's not going to be successful. Cost and ease of manufacture should be factors in any engineering decision.

manufacturer

[GMail Troll]

The design process for motherboards in my experience seems to depend on the manufacturer. Some take a more sloppy approach where the first version is riddled with bugs - take a look at Via's KT133 and subsequent KT133a for example (in some ways reminiscent to me of Redhat's notorious .0 releases). In general I'm more in favour of a rigourous approach when designing hardware - bugs in software are easy to fix (download a patch), but with hardware you expect what you're buying to work.

All in all a motherboard is a complicated piece of electronics so it isnt surprising that bugs sometimes creep in. As with software I expect it is the quality of the engineers working on it that is the ultimate deciding factor in the quality of the final product.

gmail invite [google.com]

Re:Doesn't make sense to me...

[Neuroelectronic]

That article kicks ass. I feel smarter already. I never knew EMI and line noise was such a problem for MoBo designers.. What a bitch that must be

Re:It would have been interesting

[Jeff DeMaagd]

The don't really have a lot of components, and they don't have a lot of layers.

Compared to what? I understand some motherboards are pretty simple looking, but the ones that tend to be in my systems can get pretty complicated.

Re:Not bad, but

[Billy69]

Erm, what happens on the mobo is really just a case of regulation, not a separate 'power supply' as such.

And board-level power regulation goes back at least as far as the IBM XT (yup, I had one, they had 7805 5v regulators on them)

But to answer the question I think you are asking, which is why doesn't the PSU supply the processor voltages, you have to think about the number of different processor and interface voltages there have been over the last few years. Processors have gone from using 5v logic supplies down to what, 0.8v now, via dozens of different steps in between. So to supply the voltage direct from the PSU would require either a PSU tied to a specific motherboard which was tied to a specific small group of processors, or a PSU with about 30 different voltage outputs. Both of these options are a lot more complex and painful than just regulating the voltage on the motherboard.

Sorry to disagree

[EightBits]

PC motherboards typically have 4 - 6 layers. That's pretty complicated. Think about routing all of the signal lines of the PCI (64-bit) bus and memory bus. If you have AGP nad PCI-X, add those in ther too. Think of all the signals going from your IDE ports and SCSI ports (if you have them) to your chipset. If you have an opteron, you have in the neighborhood of 940 pins. They all get connected. That's a lot of nets and a lot of routing!

And, it's a good thing to reduce board layers to a certain point because adding layers gets expensive! While it does complicate the process, the process of routing the board is a one time process and thus a one time cost. Once the board is routed and tested, it's off to manufacturing where the cost of extra layers is recurring. It does complicate the manufacturing process in that now you have to glue together more layers after routing them. This is why more layers get so expensive. Those layers have to line up. With nets getting as small as they do, there is almost no room for error in lining these layers up. Very difficult. The more layers you add, the more likely you are to have layers aligned improperly. Someone has to eat the cost of those boards that cannot be sold and it wont be the manufacturer.