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BQ51025: BQ51025 EVM DESIGN FILES BGA FOOTPRINT

Part Number: BQ51025

The BQ51025YFP footprint in EVM design files show a 6/10 VIP, hence, a 2mil annular ring on a .062 4-layer stackup . I'm curious, does this not present manufacturing or reliability challenges in a production environment? I'm pretty sure it's the least expensive way to escape the BGA but I'm not sure it even meets IPC Class 1. Is this a recommended layout? 

  • We have not see problems with manufacturing the bq51025 EVM or similar units.
  • I would love to talk to the board house that made the EVM. Mine wants me to got to .4mil laser drill for the VIP  and fan out no more than 1-layer down then adjust dialectric thickness accordingly. Which would be fine except its on one of four rigid segments in a 6-layer rigid-flex design. If I change the dialectric in this one segment it upsets impedance control throughout. I can use different stackups in each rigid segment but that would add even more process steps and cost. I need to keep the production cost down.