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On the one hand, PCB layouts are considered copyrighted information, and copying them verbatim is a bad idea for legal reasons.

On the other hand, the PCB layout of an evaluation board is pretty much a reference design for how to Do It Right.

Are there any issues with copying the eval board as closely as possible? I would assume that it's meant to be copied, as their primary goal is for you to keep buying their chips and not have problems with them, but I've never seen this specified anywhere and the datasheets and eval board manuals still have the standard "All Rights Reserved", etc.

Reproduction of information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive business practice. TI is not responsible or liable for such altered documentation.

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  • \$\begingroup\$ Is this really the place to ask about legal advice? Some companies, probably almost all will allow this, but make sure you ask them first. \$\endgroup\$ – Thomas O Nov 16 '10 at 22:13
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I think that this situation is mostly because chip manufacturers are not particularly savvy about copyright law. You should definitely copy their eval boards as closely as possible and feel good about doing so. The manufacturers make eval boards so that you can use their chips; they're happy to have you follow their examples.

The only exception that I can think of would be if you were planning to sell the resulting board as an eval board in competition with the manufacturer. But that seems like approximately the most tedious possible occupation, so I assume that's not your intent.

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    \$\begingroup\$ +1 for "not particularly savvy about copyright law." Ugh. \$\endgroup\$ – Kevin Vermeer Jul 30 '10 at 1:24
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    \$\begingroup\$ I have seen many reference designs, even reference firmware, that notes you only have rights to use it if your use their chipset. \$\endgroup\$ – Kortuk Jul 30 '10 at 1:46
  • \$\begingroup\$ @Kortuk: A good point-- I wouldn't be so cavalier in ignoring copyright law if you were using a competitor's chipset. That seems like a straightforward violation that would be hard to defend (assuming we're talking about reusing the PCB layout, not just the schematic). \$\endgroup\$ – pingswept Jul 30 '10 at 2:58
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    \$\begingroup\$ I've spoken with Microchip employees at ESC, and they said the company makes all its money on selling large quantities of its ICs, so they really don't care about making a profit on dev boards or programmers. That's why they will replace a broken programmer even if you damaged it. So I imagine the same concept applies to their designs, as long as you're going to use their ICs and not trying to compete with them. \$\endgroup\$ – Jeanne Pindar Jul 30 '10 at 22:55
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    \$\begingroup\$ Wait, if you're using a competitors part, wouldn't you use the competitors reference design? It not like these things are generic (well, 95% of the time). \$\endgroup\$ – Connor Wolf Jul 31 '10 at 5:12
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What elements of the PCB layout do you want to copy? Do you want to use good practices that happen to be implemented on the PCB (as unlikely as that is...)? In that case, go right ahead!

I don't know that an eval board PCB is a reference for "how to Do It Right" for an application you plan to sell. Your product will be different - probably more space constrained, more power sensitive, more EMI sensitive, lacking some peripherials and including others. This will change a lot of things in subtle ways. I think you can feel free to start with their basic layout, and definitely use their recommended ground plane geometry (if they provide one), but tweak it to your needs.

The schematic, on the other hand, is often the definitive reference you are looking for. I'd start with what I needed from the schematic, add my components, and then begin layout. You could have the board on your desk for reference, but I don't think you should put too much stress on exactly copying the traces.

However, you say that you want to "copy the eval board as closely as possible." I assume you want to just use a few peripherials or the interface so that you can interact with it as if it were the eval board, but if your meaning here is to produce a copy of the eval board, and sell it in competition to the manufacturer, then you're treading on thin ice. Make your own design from scratch (You must unlearn what you have learned!), and make it better than and more cheaply than the standard eval board, and you'll have something to sell.

In the end, though, there's only so many ways you can do it! The decoupling caps must be placed right next to the chip. Whether or not a judge would understand this is a whole different story...

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  • \$\begingroup\$ Good answer. To sum it up a different way: Eval designs are rarely copyable because your design will usually have many additional components that impose many more layout constraints than the eval board designer had to deal with. Even the schematic tends to change, especially in regards to choosing number and size of decoupling caps based on PCB power/ground layout and needed total capacitance on the power signals to reduce EMI emissions. \$\endgroup\$ – Mark Jul 30 '10 at 15:10
  • \$\begingroup\$ For a lot of circuits, the layout is critical, and I think it's best to start with their circuit and layout, and then modify it as minimally as possible to get the functionality you need. \$\endgroup\$ – endolith Jul 30 '10 at 16:46
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    \$\begingroup\$ Most power supply eval boards from National are laid out quite well, typically optimizing area (which is often the selling point) while minimizing high current loop area. Your layout may dictate a differently shaped area or other considerations, but it's a good medium to start with. \$\endgroup\$ – Nick T Nov 16 '10 at 18:34
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There is a distinction between evaluation boards and reference designs. Manufacturers even provide Gerber files for the latter, so that they can be copied exactly.

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