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Is there a specification or "Best Practices" in the PCB design regarding the dimension between Components? What I need is to minimize the whole PCB board BUT with enough spacing between components (for the installation/replacement of the components, or any activities that will needs soldering/de-soldering)

Note: I'm looking for an advice for the "manually" placing/soldering

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  • \$\begingroup\$ You'll mainly need to look at what your manufacturer has to work with. Like IR rework stations can let you get away with 40mil clearance to a BGA, but hot air might require no nearby small components if you don't want it to be a mess. \$\endgroup\$ – Zekhariah Mar 31 '19 at 6:51
  • \$\begingroup\$ Thanks @Zekhariah for your reply, I'm looking for that clearance for the "hot air" process to not "be a mess" :) \$\endgroup\$ – MsAmeen Mar 31 '19 at 7:19
  • \$\begingroup\$ First of all - do not design for failure. Design for reliability. \$\endgroup\$ – filo Mar 31 '19 at 9:25
  • \$\begingroup\$ @filo Sometimes you want to design for failure. Like input protection circuitry--there's a reason fuses often go in sockets instead of directly to the board. \$\endgroup\$ – Hearth Mar 31 '19 at 15:27
  • \$\begingroup\$ I would rather try to design it to survive the worst case transients. Fuses can be resettable ;) \$\endgroup\$ – filo Mar 31 '19 at 15:58
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I don't think there is a standard. It is highly personal. I personally have found that 100 mil pitch on 0805 components is slightly too crowded for me when manually placing the components. Doable, but I prefer 110 or 120 mil pitch nowadays.

Also: why will you service you board? If properly designed no component should be expected to fail. I would suggest: don't overoptimize for space and gain some experience about what /needs/ service while you also gain experience in what you own service minimums are....

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  • \$\begingroup\$ Thanks @rew for your reply, so if your 120 mil between components (edge to edge) is working good for you, I think this is what I'll follow for now. \$\endgroup\$ – MsAmeen Mar 31 '19 at 7:12
  • \$\begingroup\$ But I didn't get your point regarding "If properly designed no component should be expected to fail", what I mean is : I'm expected that some day my board will need to be repaired (like all other electronics boards) \$\endgroup\$ – MsAmeen Mar 31 '19 at 7:16
  • \$\begingroup\$ The 120 mil is center-to-center. When you respect the manufacturers "Safe Operating Area", most components last more or less indefinitvely. Components that fail are often: * External factors: Someone connected 12V to the 5V power-input. * hidden exceeding of the SOA. Sometimes you can (briefly) exceed the specs in the datasheet and the component will survive most of the time. But in due time it'll fail. * problematic components: Electrolytic caps age. Especially with high temperature and close to their max spec. \$\endgroup\$ – rew Mar 31 '19 at 9:37
  • \$\begingroup\$ When you want to minimize the whole PCB: use 0603 instead of 0805 at 75 mil or 100 mil centre to centre. I use a 1.5 mm (59 mil) centre to centre, which allows a 0.2 mm trace between them (and 0.2 copper-to-copper clearance). \$\endgroup\$ – Huisman Apr 1 '19 at 10:27
  • \$\begingroup\$ Note the answer only applies when there are no safety / high voltage clearances required! \$\endgroup\$ – Huisman Apr 1 '19 at 10:29

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