Tellabs - 2009 PCB TLA overall winner

Tellabs - 2009 PCB TLA overall winner

The 2009 Technology Leadership Awards competition featured stiff competition in all categories. In addition to winners in each industry category, an overall winner was also selected. Tellabs Operations won this award with a ‘telecom, network controllers & line cards’ category entry.

Overall winner: Tellabs Operations

Design team: Stephen Mihal, Steven Everly

End product use: Sonet switch module for optical transport product

Stats:

Design challenges:

• Design for…signal/power integrity, cost, manufacturability and reliability.
• The most complex component was a 1669 FBGA with numerous tight constraints to DDR2 banks and 6.25 Gbps signals to a backplane connector.
• Tight timing margins required extensive constraint formulas – with tons of diff pairs, ground shielding and curved traces (e.g. diff pair tolerances down to 0.001”). Over 90% of the nets had high-speed constraints.
• Signal, power and thermal constraints evolved as the layout was underway, requiring updates.
• On-board primary 48 volt and filtered secondary power required trace rules for current carrying capacity and lightning protection. The protected secondary power fed the boards 12 main power rails, this in turn fed 120 filtered powers within the rest of the design.
Preparing Recommendations
• Had tight time constraint, so used 2 layout designers simultaneously – also worked concurrently with engineering.
• Thermal simulation determined the need for 5 BGAs to mount spring clip heat sinks and 1 BGA requiring a heat pipe to cool the device.
• The 6.25 Gig routes required the through board vias to be back-drilled.
• Manual pin swapping was required to reduce trace crossing and improve signal integrity on all 6.25 gig traces.
• 300 pin fiber optic tuner and fiber cables required close interaction with mechanical and manufacturing groups to ensure cable radiuses were not violated and that a heat sink fiber optical cable carrier was viable.

Design tools:

• Expedition Enterprise flow
  (DxDesigner, CES, Expedition PCB, XtremePCB, FabLink XE, HyperLynx)
• “The use of XtremePCB, the use of cluster attributes to group components quickly to finalize the design floorplan, and the ability to cross probe between the design and schematic or CES database were crucial to our success. “
• “Utilized XtremePCB to double-team during the entire layout design phase – floorplan, placement, fan-out, defining power layers, routing and trace tuning.”
• “HyperLynx simulation was run to model design considerations. “

Judge’s comments:

“Another design in the hands of a very capable team. Excellent use of the layer stack.”

Design images:

   

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