12 V to 5 V / 1 A Buck Molecule (TPS54202), built by Gemini 4 Argon in KiCad

Status: finished and verified. Complete 28 x 20 mm 2-layer synchronous buck converter molecule (12 V nominal input, 9 V to 16 V range, 5.0 V / 1.0 A output at 500 kHz) built and verified in KiCad with adom-aiflow.

The build, start to finish

Gemini 4 Argon in Google Antigravity, inside Adom Hydrogen, builds this board from a one-sentence prompt, guided by adom-aiflow, in KiCad: It used 5.6 % of the weekly Antigravity quota on Google AI Ultra.

Argon video: the review draft

Video draft

The YouTube video of this build, "Can Gemini 4 Argon Design a PCB?", is cut and waiting for John's voiceover. The draft shows the full video with its drafted title, description, chapters, thumbnail and subtitles. Watch it to review the edit or to record the narration over it. Review the draft · Watch it on YouTube (unlisted)

Components

Every part on the board, each linked to its own wiki page (symbol, footprint and 3D model).

Part	Qty	Refs	Value	Role	Buy
TPS54202DDCR Texas Instruments	1	U1	TPS54202DDCR	sync buck, 4.5 to 28 V in, 2 A, 500 kHz	Mouser 595-TPS54202DDCR
AMPLH5030S-150MT Abracon	1	L1	15 µH	output inductor	Mouser 815-AMPLH5030S-150T
EEE-FK1V470P Panasonic	1	C1	47 µF 35 V	input bulk, damps the input cable	Mouser 667-EEE-FK1V470P
CC1206KKX7R8BB106 Yageo	2	C2, C3	10 µF 25 V X7R	input ceramic, the hot loop	Mouser 603-CC126KKX7R8BB106
0603B104J500CT Walsin	3	C4, C5, C10	100 nF 50 V	VIN bypass, bootstrap, bypass	Adom stock
CL21A226MPQNNNE Samsung Electro-Mechanics	3	C6, C7, C8	22 µF 10 V	output capacitors	Adom stock
0402N680J500CT Walsin	1	C9	68 pF 50 V	feedback feed-forward	Adom stock
CR0402-FX-3303GLF Bourns	1	R1	330 kΩ	enable divider, top	Adom stock
CR0402-FX-6802GLF Bourns	2	R2, R3	68 kΩ	enable divider, feedback top	Adom stock
CR0402-FX-5601GLF Bourns	1	R4	5.6 kΩ	feedback trim	Adom stock
CR0402-FX-1002GLF Bourns	3	R5, R6, R7	10 kΩ	feedback bottom, divider	Adom stock
CR0402-FX-1001GLF Bourns	1	R8	1 kΩ	LED current	Adom stock
IN-S63BTG Inolux	1	D1	green LED	power indicator	Adom stock
MachineContactMedium Adom	6	J1, J2, J3, J4, J5, J6	machine contact	edge contacts: VIN, GND, EN, VOUT, VMON	Adom stock
MachinePinMediumShort Adom	4	MP1, MP2, MP3, MP4	machine pin	corner pins (mechanical)	Adom stock

Install every part in KiCad

This page is a KiCad Plugin and Content Manager repository. In KiCad, open Plugin and Content Manager, Manage..., add this URL, then install adom-aiflow from the Libraries tab:

https://wiki.adom.inc/api/pages/adom/argon-buck-12v5v-molecule/files/pcm/repository.json

The library appears as PCM_tps54202-12v-5v-buck-20261018 (package inc.adom.wiki.john.tps54202-12v-5v-buck-20261018): every symbol, footprint and 3D model of this board, from the parts' wiki pages.

Assembled Board, Layout, and Electro-Thermal Verification Gallery

Figure 1: Assembled 3D TPS54202 buck converter molecule in KiCad 3D Viewer showing laser-etched components, top and bottom silkscreen tags, and corner MachinePinMediumShort anchors.

Figure 2: Complete schematic drawn live in KiCad Schematic Editor using symbols from the board PCM library (PCM_tps54202-12v-5v-buck-20261018).

Figure 3: Routed and poured 2-layer PCB layout in KiCad PCB Editor with staged two-sided silkscreen labels and zero DRC violations.

Figure 4: Whole-net copper verification highlighting GND (92 items), VIN (41 items), VOUT (33 items), and SW (10 items) across F.Cu (82.14% coverage) and B.Cu (91.51% coverage).

Figure 5: 3D electro-thermal DC current-density distribution across F.Cu and B.Cu (SW peak 45.61 A/mm2, GND 16.17 A/mm2, VIN 15.73 A/mm2, VOUT 10.26 A/mm2 vs. 50 A/mm2 budget).

Figure 6: Still-air (+41.6 C peak on U1, +40.5 C on L1) and moving-air (+21.5 C on U1, +20.3 C on L1) temperature rise maps vs. 55.0 C maximum rise budget.

Figure 7: Interactive 3D electro-thermal walkthrough in Adom Fields verifying current necks and thermal spreading across the assembled molecule.

Engineering Datasheet and 3D Assets

• Assembled Board 3D Model (ENIG Copper GLB): build/board.glb
• Assembled Board STEP Twin: build/board.step
• Project Engineering Datasheet (PDF): docs/datasheet.pdf

How this board was built

Every step of the build, in order, each with its own page of evidence (checks, screenshots, the AI's drawings and usage), written by adom-aiflow as the run went.

1. Intake: read the prompt and the requirements. The evidence

2. Design rules: choose the fab, load its design rules. The evidence

3. Circuit design: datasheet math and part values. The evidence

4. Test plan: what to measure on the workcell, a probe spot for each. The evidence

5. Sourcing: every part in stock, with an MPN. The evidence

6. Parts on the wiki: every part's wiki page, shown as it is picked. The evidence

7. Project page: README rev 1, component table, KiCad PCM repo. The evidence

8. Library: symbols, footprints and 3D from the wiki. The evidence

9. Schematic: drawn live, checked against the netlist. The evidence

10. SPICE simulation: the drawn schematic in SPICE: start-up, ripple, load step. The evidence

11. Components: wiki component identity and CAD audit. The evidence

12. 3D models: every 3D model bound and upright. The evidence

13. Placement: parts placed for current and heat. The evidence

14. Routing: every trace routed, DRC clean. The evidence

15. Heatsink vias: via arrays under the hot parts. The evidence

16. Copper pours: copper pours and stitching. The evidence

17. Rounded corners: sharp board corners rounded. The evidence

18. Current: current density on every loaded net. The evidence

19. Thermal: temperature rise against the budget. The evidence

20. Fields: current and heat solved in 3D. The evidence

21. Pour walkthrough: each pour net lit in turn. The evidence

22. Silkscreen: labels, polarity, pinouts, both faces. The evidence

23. 3D board: the finished board in 3D. The evidence

24. Finish line: 0 unconnected, 0 errors, every check passed. The evidence

25. Gerbers, BOM, CPL: manufacturing files written and checked. The evidence