Package Layout Recommendation; Bga 216 0.8 Mm Pitch Design Example; Table 9. Bga 216 0.8 Mm Pitch Package Information - ST STM32F4 Series Application Note

AN4488
8.5

Package layout recommendation

8.5.1

BGA 216 0.8 mm pitch design example

Package information (mm)
Number of rows/columns : 15x15
Package solder Pad: SMD
With 0.8 mm pitch BGA balls, fan-out vias are needed to route the balls to other layers on
the PCB. Through-vias are used in this example, which cost less than blind, buried vias. For
four adjacent BGA land pads, it is possible to have only one via as showing in
Figure 25. The traces are routed of two first row and two first colon without fan-out via. The
current pitch size allows to route only one trace between two adjacent BGA land pads.
Figure 26
signals. These signals can be optimized to achieve the routing and length matching in an
another layer before connecting to an SDRAM IC.
Recommended PCB routing guidelines for STM32F4xxxx devices

Table 9. BGA 216 0.8 mm pitch package information

Ball pitch : 0.8
Ball size : 0.4
shows an example of ideal SDRAM signals fan-out vias with power and gnd
Figure 24. BGA 0.8mm pitch example of fan-out
Design parameters (mm)
Via size : hole size ∅= 0.2, pad size: 0.45, plane clearance: 0.65
Trace width : 0.10/0.125
Trace/trace space : 0.10/0.125
BGA land size (Ball pad): ∅= 0.4, solder mask: 0.5
AN4488 Rev 7
Figure 24 and
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