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I'm laying out a fairly compact PCB (first SMD design of this degree) and am concerned about how close some of my SMD components are getting.

I've been unable to find any guidelines or advice online for how close I can place SMD components.

My concerns are:

  • Components sticking/soldering themselves together
  • Placing low components right next to high components in case the pick and place head can't get in there (i.e. 0402 right next to large connector)

I don't have a fab in mind at this stage, so I'm hoping to get some general/safe rules of thumb.

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    \$\begingroup\$ Look at some high component count smd boards. Things are really packed in. As for as a the height issue, a smart pick and place routine would fill in those smaller ones before the larger ones. Doing anything different would be stupid. Even if the p&p vacuum head is very very small. \$\endgroup\$ – Passerby May 6 '14 at 22:01
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Are you planning on using PCB fab house and then hand-assembling?? If so, 0402 might be a tad ambitious if you've never done anything like this before.

Each board house will have a list of specifications of what they can make. Some have two sets of rules or more - rules that can be used for fast and cheap, for fast and expensive, and for anything you'd like, but it gets slow and fairly expensive.

http://www.pcb-specification.com/uk are the rules for pcb-pool.com--you'll see them if you click "Design Rules". They give you files to use to set up design rules in Eagle and in Altium, two popular schematic and board layout tools. They'll even include a free metal stencil for solder paste.

If you're planning on using a fabricator, make them earn their NRE's! Send them your design, mention your concerns, and ask them for advice. It won't cost you a dime more to use their expertise in this way. If you plan on a pick-and-place process, be sure to ask them about where they want their fiducial marks.

Lastly, don't be afraid to post the board on this site, and ask for a quick design review. Be sensible, though, and make sure you provide good detail for the problem areas you suspect, and maybe tightly focus the question on that.

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  • \$\begingroup\$ Yeah, I've opted for 0603 to make hand assembly easier. It's made things a little tighter, so I'm reshuffling the layout. I'm trying to leave at least 0.5mm clearance between components for my first pass. Thanks for the link and fab info. \$\endgroup\$ – Darian May 8 '14 at 5:59

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