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I am new to designing PCB boards.

I have been working on a data acquisition board and it seems that four layer board will be correct way to go about it.

But there are a lot of different voltages required for different components.

These are mainly

  • +15V,
  • -15V,
  • +7V,
  • +5V,
  • -2V,
  • 2.5V, etc.

I can't figure out a strategy on how to get these voltages, and how the power plane fits into the picture.

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  • \$\begingroup\$ What's your application? What do your signals look like (number of signals, amplitudes, bandwidths, targeted sampling rates)? \$\endgroup\$ – Marcus Müller Jun 4 '16 at 11:15
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Good layout requries proper planning of the power distribution first.

To achieve this, you should plan the layout such that components that form a logical group are placed near each other; from this, separation of functions becomes much easier to achieve.

If you are in a mixed signal environment with sensitive analogue signals, then there is an excellent article on planning the planes.

If you are using glue logic that is fairly recent, it will have fast rise and fall times which will definitely couple energy to nearby planes and tracks.

If you are using ADCs for data acquisition, then there is another excellent article on the subject.

On that note, ADC manufacturers have helpfully grouped all the analogue signals together so that effective noise isolation may be achieved. See the device below for an example:

ADC zone separation

I also went into some detail on this subject at this previous answer.

Good layout does not have a one size fits all, but there are accepted best practices.

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For someone new to board layout, four layers definitely is a challenge.

So, first of all I'd like to strongly recommend looking into making your board more modular. You surley don't need all these voltages at the same place, so routing them only to the parts of the board where they are needed is strongly recommendable. From your question's tags, I'd presume you can have one or two voltages that you distribute across the board and have the voltage regulators that generate the locally needed voltages right where they're needed – that should solve a lot of the complexity issues.

"Data acquisition" doesn't even necessarily sound like you'd need a power plane layer; it's often a good idea to have a ground plane layer, but unless your data acquisition happens at millions of samples per second, with low pass filters (you'll need those, anyway! Never use an ADC without an appropriate filter – you'll get a lot of aliasing!) closely locateed before your digitizers' inputs, you should usually get away with simply making sure you have a continuous ground plane below your most sensitive signal lines, where you especially avoid fastly switching signals.

Other than that, PCB design is both a thing of experience (so go ahead and layout your PCB, look at the result, throw it away, do it again with all that you've learned), and of schooling – you might want to get a good book on that. Books are cheaper than broken PCB manufacturing, and much less frustrating. Believe me.

Another word of advice: Don't reinvent the wheel. You don't say what your application is, but chances are, someone before you has done something similar enough for you to buy or learn from that.

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  • 1
    \$\begingroup\$ good advice to do it once, then throw it away and start over with what you've learned. It'll be a lot faster on the second try and the layout will be better for sure. \$\endgroup\$ – Nils Pipenbrinck Jun 4 '16 at 11:29

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