@tscircuit/dogbone-solver

Local BGA pad-to-via fanout using the regular BaseSolver interface from @tscircuit/solver-utils. Escapes connected pads to adjacent interstitial vias; it does not route to a component boundary.

import { DogboneFanoutSolver } from "@tscircuit/dogbone-solver"

const solver = new DogboneFanoutSolver({
  input: simpleRouteJson,
  fanoutRoutingLayers: ["inner1"],
})
solver.solve()
if (solver.failed) throw new Error(solver.error!)
const traces = solver.getOutput()

Inputs and output positions are right-handed board-world points in millimeters (+X right, +Y up, +Z above). The solver uses the first physical source pad in each SRJ connection, its component's two-dimensional SMT grid, and phase clearance and via rules. Output routes have straight/45-degree local escapes and through vias. Unavailable layers or infeasible sites fail rather than emitting partial output. This is local escape geometry, not plane connectivity or length matching.

step(), getConstructorParams() and visualize() support replay and debugging. The fanout-solver pad-site matcher's bounded search is atomic per component; subsequent steps validate and construct each escape. DogboneAutorouter provides an asynchronous routing adapter with scheduled batches, progress graphics, start/end callbacks, cancellation and an updated downstream SRJ. Subsequent routers must preserve the completed dogbone traces as fixed copper.

Development

• bun install
• bun test — labeled SVG snapshots for AM3352, bottom-layer handoffs, blocked sites and replay.
• bun run typecheck and bun run format:check
• bun run start — Cosmos with GenericSolverDebugger pages.
• bun run build:site — export the interactive debugger.

The AM3352 fixture is the SRJ from the core AM3352 ZCZ test: 324 pads at 0.8 mm pitch, including 43 VSS and 76 supply/capacitor-related pads. Supply domains retain separate nets. It is a full-pad geometry stress test, not a complete circuit. The footprint/ball map originated in the AM3352 routing experiment and TI SPRS717L. It uses 0.4 mm pads, 0.1 mm traces and 0.3/0.15 mm vias.

Packaging

Bootstrapped following the tscircuit handbook with the official plop templates. Source-only TypeScript package (lib/index.ts), no checked-in lockfile or build artifact. CI validates tests, types and formatting. The release workflow publishes versioned GitHub Packages, served by jscdn: https://jscdn.tscircuit.com/@tscircuit/dogbone-solver/<version>.

Visual regression gallery

To inspect the debugger locally, open the am3352 or small-grid page in the Cosmos sidebar. On hosts with exhausted filesystem watchers, start with CHOKIDAR_USEPOLLING=true bun run start.