STPCI01 STMicroelectronics, STPCI01 Datasheet - Page 65

• Manufacturer Part Number: STPCI01
• Description: STPC INDUSTRIAL - PC COMPATIBLE EMBEDED MICROPROC
• Manufacturer: STMicroelectronics

The PBGA Package also dissipates heat through
the peripheral ground balls. When a heat sink is
placed on the device, heat is more uniformly
spread throughout the moulding, increasing the
dissipation of heat through the peripheral ground
balls.
The higher the number of via pads connected to
each ground ball, the higher the amount of heat
dissipated. The only limitation is the risk of losing
routing channels.
Figure 6-1
between thermal dissipation and the number of
routing channels.
A local ground plane on the opposite side of the
board, as shown in
dissipation. It is used to connect decoupling
capacitors but can also be used for connection to
a heat sink or to the system metal box for better
dissipation.
This possibility of using the whole system box for
thermal dissipation can be very useful in cases of
high internal temperature and low external
temperature. In such cases, both sides of the
PBGA should be thermally connected to the metal
chassis in order to propagate the heat flow
through the metal.
example.
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
shows a routing with a good trade off
Figure 6-3
Figure
Figure 6-4. Optimum Layout for Central Ground Ball
6-2, improves thermal
illustrates a typical
Issue 2.4 - February 11, 2002
Clearance = 6mil
External diameter = 37 mil
Via to Ground layer
hole diameter = 14 mil
Solder mask
diameter = 33 mil
Pad for ground ball
diameter = 25 mil
connections = 10 mil
BOARD LAYOUT
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