tscircuit / tscircuit/footprinter

tqfp44 generates a 0.5mm pitch with 0.30mm pads, but TQFP-44 is a 0.8mm-pitch part

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Dominant language
TypeScript
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Forks
128
Avg merge
16h 30m
Merged PRs (30d)
6

Description

What happens

fp.string("tqfp44") (and tqfp44_w10) produces a 44-pin QFP on a 0.5mm pitch with 0.30mm-wide pads.

What it should be

TQFP-44 is standardized as a 10x10mm body on 0.8mm pitch (JEDEC MS-026 BBA). KiCad's TQFP-44_10x10mm_P0.8mm uses 0.8mm pitch with 1.475 x 0.55mm pads. footprinter already emits exactly those values for its sibling TQFP-32, which is also a 0.8mm-pitch part. The current output matches no real TQFP-44, so a board that uses tqfp44 gets pads at 0.5mm pitch instead of 0.8mm and too narrow to sit under the leads.

Root cause

In src/fn/tqfp.ts the pitch and pad-width defaults place case 44 in the 0.5mm-pitch, 0.30mm-pad group with 48/64/100. TQFP-44 belongs with case 32 (0.8mm, 0.55mm).

Evidence
footprinter tqfp44 KiCad TQFP-44_10x10
pitch 0.5mm 0.8mm
pad width 0.30mm 0.55mm
pad length 1.475mm 1.475mm

I have a fix ready with a kicad-parity test and will open a PR.

Contributor guide

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First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start in src/fn/tqfp.ts and inspect the defaults for cases 32 and 44, then run the kicad-parity test mentioned in the issue. Confirm that tqfp44 and tqfp44_w10 match the KiCad TQFP-44_10x10mm_P0.8mm pitch and pad dimensions, while preserving the existing sibling behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
typescript
Domain
tooling
Issue type
Bug
Difficulty
2/5
Estimated time
1-3 hours
Activity status
Active
Clarity
Clearly specified
Newbie friendliness
48/100

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