fix: add vson footprint by joncherry · Pull Request #431 · tscircuit/footprinter

joncherry · 2025-11-23T06:48:38Z

/closes #182

Summary

Add vson for various pin and pad configurations based on search results for search term "vson" in kicad viewer.
added as tests:

HOT TIP: clicking "source" next to the title in kicad viewer will show exact numbers which is more precise than taking measurements with the "d" hotkey.

(<-click to expand) AI overview of some vson meaning:

The term VSON-10-1EP_3x3mm_P0.5mm_EP1.65x2.4mm is a specific footprint name used in printed circuit board (PCB) design software (like KiCad or Altium) to define the physical layout and dimensions for a specific electronic component package. Here's a breakdown of what each part of the name means:

VSON: Stands for Very Thin Small Outline No-lead package. This is a type of surface-mount technology (SMT) component that has contact pads on the bottom periphery and no leads extending from the sides, offering a low profile.
10: Indicates that the package has 10 pins (or contact pads) for electrical connection to the PCB.
1EP: Signifies one Exposed Pad (EP). This is a large, central thermal pad on the bottom of the component, which is soldered to a corresponding pad on the PCB to help dissipate heat from the integrated circuit.
3x3mm: Specifies the overall body size of the component package, which is 3mm by 3mm.
P0.5mm: Refers to the pitch of the peripheral pins, meaning the center-to-center distance between adjacent pins is 0.5 millimeters. This is a fine pitch requiring precision manufacturing and assembly.
EP1.65x2.4mm: Provides the specific dimensions of the central Exposed Pad, which is 1.65mm by 2.4mm.

In summary, this footprint name is a precise instruction for the PCB design software to create a land pattern (the copper pads on the PCB) that matches the physical specifications of a 10-pin VSON component with a central thermal pad, ensuring the component can be correctly placed and soldered onto the board.
For more information on specific packages, you can often find detailed package drawings and land pattern recommendations in the datasheets provided by component manufacturers like Texas Instruments or Onsemi.

tests/vson1.test.ts

techmannih

Footprints looks good can you please add kicad parity to varify all of them.

joncherry · 2025-11-25T21:00:38Z

Footprints looks good can you please add kicad parity to varify all of them.

I am running into the problem that the parity tests expect json from kicad but all of the kicad footprints I have are "*.kicad_mod" instead of json. https://kicad-mod-cache.tscircuit.com/Package_SON.pretty/VSON-8-1EP_3x3mm_P0.65mm_EP1.65x2.4mm.kicad_mod
do we have a means of coverting those into json for the parity test? if not I would need to build a converter to json to be able to add parity tests.

Edit: figured out that I just need to change the file extension on the url.

joncherry · 2025-11-25T21:31:16Z

tests/kicad-parity/__snapshots__/VSON-8_3.3x3.3mm_P0.65mm_NexFET_boolean_difference.snap.svg

This discrepancy with kicad appears to be happening because of a difference between these 2 files

https://kicad-mod-cache.tscircuit.com/Package_SON.pretty/VSON-8_3.3x3.3mm_P0.65mm_NexFET.circuit.json

https://kicad-mod-cache.tscircuit.com/Package_SON.pretty/VSON-8_3.3x3.3mm_P0.65mm_NexFET.kicad_mod

in the kicad mod, there are pins with both 1.44 and -1.44, but in the circuit json there is only -1.44

both have the same 0.385 x offset for the central exposed pad which can be identified in the json by its dimensions of width 1.9 and height 2.45

techmannih · 2025-12-02T04:50:48Z

src/fn/vson.ts

+  grid: dim2d,
+  ep: dim2d.default("0x0mm"),
+  epx: length.default("0mm"),
+  pinw: length,
+  pinh: length,


please describe them.

pinw is pin width and pinh is pin height. This allows the pin squares to match the numbers in kicad viewer.
I can add a code comment saying that if that would be a good thing to do.

@joncherry I understand, but we’ve never used these before your PR. It would help a lot if you could describe the EO and EPX more clearly, and also explain what the fgrid is used for.

I have added code comments to describe them.

chore: add code-comments to vson_def params
b3475dc

tests/kicad-parity/vson5_kicad_parity.test.ts shows a decent example of them getting used.

The name VSON-8_3.3x3.3mm_P0.65mm_NexFET is what is shown in kicad viewer.

from the kicad name we get the first part of the test VSON8_grid3.3x3.3mm_P0.65mm but to make the footprint match we need the rest of the numbers from the kicad source file so it uses addition functions/params _ep1.9x2.45mm_epx0.385mm_w2.88mm_pinw0.63mm_pinh0.5mm

I suppose that the reason these extra functions/params are needed is because the vson.ts file is used for multiple footprints instead of using individual files for each footprint (for example vson8_3.3x3.3mm_p0.65mm_nexfet.ts) with hardcoded values for the extra data that is not in the name from kicad viewer.

techmannih · 2025-12-02T04:53:20Z

tests/kicad-parity/vson3_kicad_parity.test.ts

+  const svgContent = convertCircuitJsonToPcbSvg(combinedFootprintElements)
+  expect(svgContent).toMatchSvgSnapshot(
+    import.meta.path,
+    "Texas_VSON-HR-8_1.5x2mm_P0.5mm",
+  )
+  expect(booleanDifferenceSvg).toMatchSvgSnapshot(
+    import.meta.path,
+    "Texas_VSON-HR-8_1.5x2mm_P0.5mm_boolean_difference",
+  )


please remove it. we never use company name

done. I removed the test (vson3 test) and renamed the test files (vson 4,5,6 -> 3,4,5) so that they still follow a numerical sequence so that the graphite review bot will stay happy.

chore: remove texas vson test
8e3a79d

techmannih · 2025-12-13T22:12:52Z

src/fn/vson.ts

+  grid: dim2d, // width and height of the border of the footprint (used for silkscreen lines)
+  ep: dim2d.default("0x0mm"), // width and height of the central exposed thermal pad
+  epx: length.default("0mm"), // x offset of the center of the central exposed thermal pad
+  pinw: length, // width of the pin pads
+  pinh: length, // height of the pin pads
+})


please use .describe() instead of comments

joncherry · 2025-12-23T16:48:58Z

Dang. Only meant to re-request review from techmannih

joncherry · 2026-01-14T21:12:32Z

@techmannih I have moved on to other projects, so I won't be working on this anymore. Anyone can feel free to take over or borrow from this PR. I hope the work I have done is useful to someone.

joncherry added 4 commits November 22, 2025 22:41

fix: add vson footprint

10fa083

fix: add vson footprint - small fix

c0b43a0

chore: add tests for no ep

0dc217c

chore: add tests for offset ep

31fbc42

joncherry marked this pull request as ready for review November 24, 2025 21:53

joncherry requested review from seveibar and techmannih as code owners November 24, 2025 21:53

graphite-app bot reviewed Nov 24, 2025

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tests/vson1.test.ts Show resolved Hide resolved

chore: rename test

591af14

techmannih reviewed Nov 25, 2025

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chore: add kicad parity tests

0bc6a30

joncherry commented Nov 25, 2025

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seveibar approved these changes Nov 28, 2025

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joncherry requested a review from techmannih November 30, 2025 01:45

techmannih reviewed Dec 2, 2025

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joncherry added 2 commits December 3, 2025 19:17

chore: remove texas vson test

8e3a79d

chore: add code-comments to vson_def params

b3475dc

joncherry requested a review from techmannih December 13, 2025 19:49

techmannih reviewed Dec 13, 2025

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joncherry added 3 commits December 23, 2025 08:37

chore: code comments to describe hints

d452368

Merge branch 'main' into vson

7b40742

chore: format file

ea407f4

joncherry requested review from seveibar and techmannih December 23, 2025 16:46

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