Figure 6-4. Optimum layout for central ground ball
BOARD LAYOUT
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
The PBGA Package dissipates also through pe-
ripheral ground balls. When a heat sink is placed
on the device, heat is more uniformely spread
throughout the moulding increasing heat dissipa-
tion through the peripheral ground balls.
The more via pads are connected to each ground
ball, the more heat is dissipated . The only limita-
tion is the risk of lossing routing channels.
Figure 6-5 shows a routing with a good trade off
between thermal dissipation and number of rout-
ing channels.
Figure 6-5. Global ground layout for good thermal dissipation
Via to ground layer
Ground pad
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Release B
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice.