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Specifically I am wondering about the mechanical strength of the surface mount connections in consumer electronics. Are some tougher than others?

I've had a few experiences where an electronic device (single board computer, intel camera, intel edison), has fallen once from a small height and as a result has become completely useless - doesn't turn on isn't recognized by computer etc.

On the other hand I have dropped my iPhone multiple times, and know lots people who have practically dropped their phones off of buildings, but apart from a shattered screen the phone almost always retains its functionality.

So why is this the case? Do phone companies expect consumers will drop their phones and make them tougher. If so why aren't all devices (cameras,SBC's,etc) made to this standard of toughness?

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    \$\begingroup\$ I once crushed an iphone with just one hand, it did seem quite fragile to me... \$\endgroup\$ – PlasmaHH Jul 28 '17 at 13:07
  • \$\begingroup\$ @PlasmaHH well, it does blend, doesn't it? \$\endgroup\$ – Sébastien Dawans Jul 28 '17 at 13:09
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    \$\begingroup\$ iphones are encased in an aluminium container. barePCB's do not have that \$\endgroup\$ – JonRB Jul 28 '17 at 13:33
  • \$\begingroup\$ Most of the cost of the iPhone is the hidden anti-grav device. \$\endgroup\$ – Andy aka Jul 28 '17 at 13:42
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    \$\begingroup\$ Bare pcbs, particularly surface mount ones, are fairly fragile unless they are designed to have covers or whatever to protect them. Engineers often work with bare eval boards etc. and it's not unusual to see damage from sheared off parts etc. especially when lent to a sloppy colleague. \$\endgroup\$ – Spehro Pefhany Jul 28 '17 at 17:20
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When looking at an iPhone logic board, it is clear that it is designed to withstand a lot of abuse. The critical and usually larger IC's, such as the SoC, PMIC, NAND are usually encased in a strong underfill while some of the passives, especially those near FPC connectors, are also covered in a softer epoxy. The vast majority of the passive devices are 0201 or 01005 and most of the IC's are micro-BGA. All of the connectors are secured with brackets so that they don't shift or get dislodged, possibly damaging the connector or surrounding components due to an impact.

So clearly there is a design side to it but I would also consider some basic physics as well. Modern smartphones are pretty light and often times inside a protective case. This makes the force of an impact much lower than other device types. For example, if an iPad or similar tablet fell from the same height, it would be more heavily damaged.

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    \$\begingroup\$ Careful with the weight thing there. Being "lighter" does not necessarily mean less shock. Weight vs surface area makes a difference and weight vs the cases ability to deform and absorb the shock all factor in. A heavy board in a foamy box can survive a lot better than a light board with a thin skin, basically no box. It gets complicated fast. +1 for the first paragraph though. \$\endgroup\$ – Trevor_G Sep 18 '17 at 17:06
  • \$\begingroup\$ Weight distribution also matters, if 75% of the weight is in one component at one end of the board it's a problem since that part wants to keep moving longer than the rest of the board. \$\endgroup\$ – Trevor_G Sep 18 '17 at 17:11

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