3.2 Dual-Trace Breakout
(Ask a Question)Dual-trace breakout employs two signal traces between two BGA pads on the outer layers, and two traces between two fanout vias on the internal signal layers, as illustrated in the following figure.
Important: Dual-trace breakout is only possible with 1 mm pitch
packages. For smaller packages, the space between two pads/vias might not be sufficient to
route two traces, and PCB fabrication is costly.
This kind of fanout needs very precise control for copper clearance and trace width, therefore, costing more than the single-trace breakout.
Important: No blind or buried via technology is employed for the
fanout.
| BGA Pins | Pitch Size (mm) | Number of Signal Layers Needed | |
|---|---|---|---|
| — | — | Dual Trace | Single Trace |
| 484 | 0.8 | 3 | 4 |
| 484 | 1.0 | 2 | 4 |
| 536 | 0.5 | — | 3 |
| 784 | 1.0 | 3 | 5 |
| 1152 | 1.0 | 3 | 6 |