With the back off of the phone, this is the
first visible bit of electronics. The space where the black sticker sits
is normally taken up by the battery.
Almost every group of components
is hidden beneath the perforated metal shields. While their primary
role is no doubt to protect against interference they can also serve
another role. As they are soldered almost completely along the perimeter
of the interface with the PCB they have the ability to pick up, an wick away,
heat from the underlying components.
There is a really good article on Aavid's site, written by
Christopher Chapman, entitled the "Basis of package/device Cooling" which
address this type of cooling setup in good detail. Briefly though, it
works on the principle that heat from the individual components is
transferred into the PCB.
Now, assuming the substrate has a metal layer, it can then
be used to aid in the cooling of the surface mounted components. In effect
the copper layer that is used for the transmission of electrical signals
can act like a thermal pathway. The tiny metal cages shown on the PCB may
- and I stress may - be acting in this capacity, in addition to their
From normal use of a phone we all know they get warm if
conversations last a while. In this case, the hottest spot seems to be on
the lower right hand side. That particular enclosure is made from
stainless steel and shows visible 'browning' just above an electrical