BOARD LAYOUT

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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.

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 6-4. Optimum layout for central ground ball

Via to Ground layer

Pad for ground ball

Clearance = 6mil

diameter = 25 mil

hole diameter = 14 mil

Solder mask

diameter = 33 mil

External diameter = 37 mil

connections = 10 mil

Figure 6-5. Global ground layout for good thermal dissipation

Ground pad

Via to ground layer