Map the controller's simultaneous workloads
TI's ADAS domain controller resources identify processing, diagnostics and mixed communication interfaces as design concerns. Turn the system block diagram into a traffic and power map that shows which cameras, network links and compute blocks operate together.
Use that map to reserve memory and high speed routes before assigning remaining space to lower priority signals. Label diagnostic and recovery connections clearly so dense routing does not make fault investigation dependent on inaccessible package pads.
Review power and cooling with package escape
A successful BGA fanout can still leave inadequate space for the power network or thermal attachment. Overlay decoupling locations, copper paths and heatsink mounting restrictions on the escape study. Compare candidate layer structures with these features present, rather than adding them after routing is finished.
Discuss mechanical strain around large packages and mounting points with the enclosure and assembly teams. Record the assumed support and fastening arrangement in the prototype test configuration; a bare board on a bench does not reproduce it.
Build a construction specific evidence request
Ask the prospective fabricator to address the proposed microvia structure, material system and test plan, not merely a broad capability category. If a stacked structure is proposed, request evidence applicable to that construction and the intended assembly exposure. Resolve differences before releasing the layout.
- Identify the package and memory interface driving each buildup layer.
- Trace sensor connectors to their actual receiver and reference layers.
- Reserve diagnostic access and recovery programming paths.
- Document thermal attachment and mounting constraints.
Keep release decisions traceable
Tie approved stackups, material substitutions and engineering exceptions to a specific hardware revision. During production transfer, compare the manufactured construction with the one used for the project's verification. A change that preserves dimensions may still affect signal, power or reliability assumptions.
Separate bare board acceptance results from assembled controller and vehicle level validation. Each provides evidence at a different boundary, and none should be represented as automatically proving the others.
Adjacent-layer access, one connection at a time
Dielectric · geometry + material
Core or build-up dielectric
Illustrative only. Copper thickness, dielectric construction and via spans require a reviewed stackup.
Common questions
Does any-layer HDI establish automotive suitability?
No. It describes routing construction. Suitability depends on the specified product requirements, supplier controls, qualification evidence and application validation.
What should be reviewed first on a dense ADAS board?
Review processor and memory escape with power delivery and thermal mechanics together. Solving those separately can create a layer stack that routes signals but cannot support the complete controller.
References & further reading
Method & assumptions · General design guidance. Validate the proposed construction and acceptance criteria for your project.