12 V to 5 V / 1 A Buck Molecule (TPS54202)

@@ -4,13 +4,15 @@  A 12 V to 5 V, 1 A synchronous buck on the TI TPS54202, designed as a 28 x 20 mm Adom molecule. -It takes the brief from the YouTube video "Hardware Design with GPT-6: Schematic, PSpice & PCB" by Inside Embedded (12 V in, 5 V at 1 A out, terminals, test points) and designs it again from scratch. Every value comes from the datasheet equations. The loop and the switching behaviour were simulated in ngspice, and the result was checked against TI's own PSpice model. The board was placed, routed, poured and analysed in KiCad 10 with adom-aiflow, and its copper was checked for current density and temperature with Adom Fields.+It takes the brief from the YouTube video "Hardware Design with GPT-6: Schematic, PSpice & PCB" by Inside Embedded (12 V in, 5 V at 1 A out, terminals, test points) and designs it again from scratch. Every value comes from the datasheet equations. The loop and the switching behaviour were simulated in ngspice, and the result was checked against TI's own PSpice model. The board was placed, routed, poured and analysed in KiCad 10 with [adom-aiflow](https://wiki.adom.inc/adom/adom-aiflow), and its copper was checked for current density and temperature with [Adom Fields](https://wiki.adom.inc/adom/adom-fields).++It was built with a set of Adom tools working together; [here is the full list](docs/tools.md).  The board has not been fabricated yet. Everything below is design and simulation.  ## The video -About four minutes, start to finish: the prompt in Adom Hydrogen, the circuit, three SPICE engines in agreement, the live layout in KiCad 10, the current and heat analysis and the rework it caused, the silkscreen placed live, the part models and their wiki pages, and what it cost to build.+About four minutes, start to finish: the prompt in [Adom Hydrogen](https://wiki.adom.inc/adom/hydrogen), the circuit, three SPICE engines in agreement, the live layout in KiCad 10, the current and heat analysis and the rework it caused, the silkscreen placed live, the part models and their wiki pages, and what it cost to build.  [![AI PCB Design for Engineers: watch on YouTube](docs/img/video-youtube.jpg)](https://www.youtube.com/watch?v=vKUMzy261zs) @@ -33,7 +35,7 @@ About four minutes, start to finish: the prompt in Adom Hydrogen, the circuit, t | thermal (Adom Fields, still air) | U1 +45 C at its GND pin, L1 +41 C; 55 C junction-based budget | | board | 28 x 20 mm, 2 layers, 0.5 oz copper, 4 medium machine pins on a 24 x 16 mm grid, 6 contacts, 4 probe pads | | DRC (KiCad 10.0.5) | 0 errors, 0 unconnected |-| sourcing | Mouser plus Adom stocked basic parts, for a 3rd party fab |+| sourcing | Mouser plus [Adom stocked basic parts](https://wiki.adom.inc/adom/adom-basic-parts), for a 3rd party fab |  ## Molecule interface @@ -55,6 +57,7 @@ Probe pads: TP1 SW (15.6, 4.9), TP2 FB (9.4, 5.6), TP3 VOUT (21.6, 4.9), TP4 GND  | guide | what it covers | |---|---|+| [The Adom tools](docs/tools.md) | Every Adom tool used on this board, what each one did, and a link to its page. | | [Circuit design](docs/design.md) | The brief, why the TPS54202, and every calculation: inductor (15 uH vs Lmin), COUT, the 68 pF Cff, the stocked-value divider search, EN UVLO, bootstrap, losses. | | [Simulation](docs/simulation.md) | ngspice loop gain across Cff, the switching transient at 9, 12 and 16 V, and the check against TI's PSpice model. | | [Sourcing](docs/sourcing.md) | The BOM with Mouser part numbers, the 3rd party fab sourcing policy, and where every 3D model came from. |

@@ -47,6 +47,8 @@ Two Kelvin connections come from datasheet 7.4.1. The divider's ground (R3.2) re  ## Placement +Placement, routing, pours and silkscreen were done by Claude in [Adom Hydrogen](https://wiki.adom.inc/adom/hydrogen), following [adom-aiflow](https://wiki.adom.inc/adom/adom-aiflow) and driving KiCad 10 live through the [Adom KiCad Bridge](https://wiki.adom.inc/adom/kicad-bridge) (part of [Adom Bridge](https://wiki.adom.inc/adom/adom-bridge)). Each step was checked against KiCad's own design rules before it was committed.+ The ten interface parts (four machine pins and six contacts) are fixed by the molecule grid. The other parts were placed around the power path, with every placement checked against KiCad's DRC before it was committed:  - the input hot loop (C2, C3, C4 to U1 VIN, to U1 GND, and back to the capacitor grounds) is tight on F.Cu next to U1;

@@ -85,7 +85,7 @@ Each key net selected as a whole in KiCad (pours, tracks, vias and pads together  <a id="clip-7"></a> -The Adom Fields app on the solved board: heat flow in each copper layer in 3D with the vias, the bottom ground plane, temperature in still and moving air, and current density.+The [Adom Fields](https://wiki.adom.inc/adom/adom-fields) app on the solved board: heat flow in each copper layer in 3D with the vias, the bottom ground plane, temperature in still and moving air, and current density.  <video src="docs/clips/window-4852048-20260929-125229-10x.mp4" poster="docs/clips/window-4852048-20260929-125229-poster.jpg" controls muted playsinline preload="metadata"></video> 

@@ -4,6 +4,8 @@ This page walks through how each part value on the molecule was chosen. The equa  ## The brief +The TPS54202 datasheet and its part data were gathered with [Chip Fetcher](https://wiki.adom.inc/adom/adom-chip-fetcher). The schematic symbols come from [adom-symbol](https://wiki.adom.inc/adom/adom-symbol) and [Adom Library](https://wiki.adom.inc/adom/adom-lbr), including the 3D chip outlines on U1, C1, L1 and D1, drawn from each part's STEP model on [Adom Step2GLB](https://wiki.adom.inc/adom/adom-step2glb), Adom's OpenCascade service.+ The brief comes from the YouTube video "Hardware Design with GPT-6: Schematic, PSpice & PCB" by Inside Embedded: 12 V in, 5 V at 1 A out, with terminals and test points. We designed it again from scratch rather than copying it. The part choice, the values, the schematic and the layout are all our own. Only the requirements are shared.  | requirement | brief | this design |

@@ -1,6 +1,6 @@ # How the video was made -The video is cut from footage captured while the board was being built, plus a few shots made afterwards. Everything here is something you can do in Adom Hydrogen for your own board.+The video is cut from footage captured while the board was being built, plus a few shots made afterwards. Everything here is something you can do in [Adom Hydrogen](https://wiki.adom.inc/adom/hydrogen) for your own board.  [Watch the video on YouTube](https://www.youtube.com/watch?v=vKUMzy261zs) @@ -8,15 +8,15 @@ The video is cut from footage captured while the board was being built, plus a f  You can't film the past, so the footage has to be recorded during the run: -- **Every step, as it happens.** adom-aiflow records a clip of each step (placement, routing, pours, analysis, silkscreen) with Adom Bridge's window recorder. Those raw clips are on the [build clips](clips.md) page.+- **Every step, as it happens.** adom-aiflow records a clip of each step (placement, routing, pours, analysis, silkscreen) with [Adom Bridge](https://wiki.adom.inc/adom/adom-bridge)'s window recorder. Those raw clips are on the [build clips](clips.md) page. - **The prompt being typed.** Record the AI thread in Hydrogen while you type the request, so the video can open on it.-- **Your apps at work.** Hydrogen shows the AI on the left and a webview on the right, which is a good frame for dashboards such as the Adom SPICE dashboard.+- **Your apps at work.** Hydrogen shows the AI on the left and a webview on the right, which is a good frame for dashboards such as the [Adom SPICE dashboard](https://wiki.adom.inc/adom/adom-spice-skillpack). - **The token cost.** Note the tokens the run used if you want a cost scene.  ## Make the shots  - **Smooth 3D.** The board orbit and the D1 close-up are rendered frame by frame from the board's 3D model in a headless browser, not screen-recorded, so they never stutter.-- **Analysis views.** The current and heat shots come from Adom Fields, captured the same way.+- **Analysis views.** The current and heat shots come from [Adom Fields](https://wiki.adom.inc/adom/adom-fields), captured the same way. - **Pages and schematics.** Wiki pages are captured scrolling, and the schematic is a high-resolution export panned with a slow, eased camera move. - **Motion in every scene.** Every shot has a gentle push-in or pan, and long recordings are sped up to their action. @@ -29,7 +29,7 @@ You can't film the past, so the footage has to be recorded during the run: | 0:15 | The board | An orbit of the finished board, rendered from its 3D model. | | 0:30 | The circuit | The KiCad schematic, with the 3D chip outlines on U1, C1, L1 and D1. | | 1:00 | Simulation | The Adom SPICE dashboard in Hydrogen's webview, with the LTspice and PSpice for TI windows driven through Adom Bridge. |-| 1:28 | Placement | KiCad 10 driven live through the Adom KiCad Bridge. |+| 1:28 | Placement | KiCad 10 driven live through the [Adom KiCad Bridge](https://wiki.adom.inc/adom/kicad-bridge). | | 1:41 | Routing and pours | The routed board, the copper pours, then each net (GND, VIN, VOUT, SW) selected in KiCad. | | 1:55 | Current and heat | Adom Fields with the parts standing on the heat map, flying in to the SW-node choke point. | | 2:10 | The rework | The reroute, the SW neck circled in KiCad, and the final heat map. |@@ -42,8 +42,8 @@ You can't film the past, so the footage has to be recorded during the run:  ## Put it together -- **Review clip by clip.** Load each scene into adom-video-post's storyboard and approve them one at a time before assembling.-- **Voice.** The voice-over is a human recording, laid over the finished cut. adom-tts works for a draft narration while you review.+- **Review clip by clip.** Load each scene into [adom-video-post](https://wiki.adom.inc/adom/adom-video-post)'s storyboard and approve them one at a time before assembling.+- **Voice.** The voice-over is a human recording, laid over the finished cut. [adom-tts](https://wiki.adom.inc/adom/adom-tts) works for a draft narration while you review. - **Thumbnail.** Built from the project's own pieces: the analysis render of the board, a Hydrogen screenshot and the Adom brand fonts. - **Hosting.** Upload a high-quality master (we used 1440p) to YouTube and link it from your page. 

@@ -6,6 +6,8 @@ We simulated the design three ways: 2. A cycle-by-cycle switching model in ngspice to check startup, ripple and load steps at 9, 12 and 16 V. 3. TI's own encrypted TPS54202 transient model in PSpice for TI, to check the first two against the vendor's model of the silicon. +All of it ran from Adom Hydrogen with the [Adom SPICE](https://wiki.adom.inc/adom/adom-spice-skillpack) skills: ngspice in Hydrogen's Linux workspace, and LTspice and PSpice for TI on a Windows PC, driven by the AI through [Adom Bridge](https://wiki.adom.inc/adom/adom-bridge).+ Every circuit uses the values from `design/calcs.json` ([design](design.md)): L 15 uH with 118 mOhm DCR, COUT 36.3 uF effective, Rtop 73.6 k, Rbot 10 k, Cff 68 pF, EN 1 M / 150 k.  ## Why a fitted model first@@ -92,7 +94,7 @@ What the comparison shows:  ## 4. Three simulators, one answer (Adom SPICE dashboard) -The fitted model was written once as a portable netlist and run in ngspice, LTspice and PSpice for TI with the [adom-spice-skillpack](https://wiki.adom.inc/adom/adom-spice-skillpack) dashboard, which measures every engine with the same code and overlays the waveforms. TI's own model is shown as a reference that does not vote.+The fitted model was written once as a portable netlist and run in ngspice, LTspice and PSpice for TI with the Adom SPICE dashboard, which measures every engine with the same code and overlays the waveforms. TI's own model is shown as a reference that does not vote.  ![Adom SPICE dashboard: ngspice, LTspice and PSpice for TI agree on all 8 measurements; TI's model as a reference](docs/img/spice-dashboard.png) 

@@ -6,7 +6,7 @@ The molecule is built for a 3rd party fab, and the fab target decides where the  | fab target | parts come from | never | |---|---|---|-| **the 3rd party fab (this board)** | Adom stocked basic parts (the pick-and-place reels) first, then Mouser | JLCPCB/LCSC-only parts |+| **the 3rd party fab (this board)** | [Adom stocked basic parts](https://wiki.adom.inc/adom/adom-basic-parts) (the pick-and-place reels) first, then Mouser | JLCPCB/LCSC-only parts | | JLCPCB | JLCPCB/LCSC parts | parts JLCPCB cannot place |  This board has no JLCPCB parts. Building it at JLCPCB would mean redoing the sourcing pass for that profile, not mixing the two profiles in one BOM.@@ -18,6 +18,8 @@ Two rules shaped the parts list:  ## BOM +Parts were found with [Adom Parts Search](https://wiki.adom.inc/adom/adom-parts-search) (Mouser, DigiKey and JLCPCB in one search), with Adom Basic Parts first for the commodity passives and LEDs.+ Stock was checked on 2026-09-29.  | ref | value | MPN | maker | package | source | Mouser PN | Mouser stock |@@ -67,12 +69,14 @@ Every footprint on the board has a 3D model. The board points at portable copies  ![Abracon AMPLH5030S manufacturer STEP](docs/img/abracon-amplh5030s.png) ![Panasonic case D electrolytic manufacturer STEP](docs/img/panasonic-case-d.png) -Every model was checked on the shared step2glb (OCCT) service with `step2glb features`, which reports the bounding box and which axis the height sits on. That check is how the three Y-up models were caught. For example, the Abracon model's 2.8 mm height lay along Y (from -0.05 to 2.75 mm). Each rotation was then confirmed in KiCad's native 3D viewer, where the part must sit on its pads.+Every model was checked on [Adom Step2GLB](https://wiki.adom.inc/adom/adom-step2glb), Adom's OpenCascade service, with `step2glb features`, which reports the bounding box and which axis the height sits on. That check is how the three Y-up models were caught. For example, the Abracon model's 2.8 mm height lay along Y (from -0.05 to 2.75 mm). Each rotation was then confirmed in KiCad's native 3D viewer, where the part must sit on its pads.  A model drawn from the datasheet dimensions is also in `kicad/3d/AMPLH5030S_AI-created.step`, labelled AI-created with a provenance file (datasheet URL, revision, page, dimensions and tolerances). The board does not use it; it uses Abracon's own STEP.  ### Part marking (laser etch) +The part numbers on the 3D models are flat laser marks made with [Adom Chip Laser](https://wiki.adom.inc/adom/adom-chip-laser).+ Every part with an MPN (U1, C1 to C9, R1 to R8) carries it as a flat laser-etch mark on the top face of its 3D model. The mark is a zero-thickness face, so it adds few triangles, and the vendor colours are kept. It runs along the part's long axis (U1, C2, C3) or, on C1, along the silver field of the can so it stays off the black polarity stripe, and on the MLCCs and chip resistors it is seated on the ceramic between the end caps. D1's mark is on the side of its lens so the window stays clear. L1's Abracon model already carries its printed AMPLH5030S marking, so it was not etched again. The [build clips](clips.md) show the board before and after.  D1 uses the coloured model from the [IN-S63BTG](https://wiki.adom.inc/adom/in-s63btg) basic-part page, now at the datasheet height (0.55 mm; KiCad's generic model was 1.1 mm): its lens is tinted to the datasheet's 527 nm dominant wavelength and softened so it looks like real epoxy.

@@ -1,6 +1,6 @@ # Current density and thermal: Adom Fields on the real copper -The board's copper was solved with Adom Fields. Fields builds a copper map from the board's filled pours, tracks, pads and vias on a 0.2 mm grid (140 x 100 cells) and computes two things:+The board's copper was solved with [Adom Fields](https://wiki.adom.inc/adom/adom-fields). Fields builds a copper map from the board's filled pours, tracks, pads and vias on a 0.2 mm grid (140 x 100 cells) and computes two things:  - **current**: a DC conduction solve for each loaded net, between its terminals; - **heat**: a steady-state solve with the layers coupled through the dielectric and every via barrel, losing heat to the air on both faces.

@@ -0,0 +1,42 @@+# The Adom tools behind this board++Claude designed this board inside Adom Hydrogen, but most of the heavy lifting came from Adom tools working together. Each one below has its own page on the Adom wiki.++To try the same flow, ask the AI in Hydrogen: *"Use adom-aiflow to design a 12 V to 5 V, 1 A buck converter on the TI TPS54202 in KiCad 10."* Naming adom-aiflow brings in the rest.++## Where the work happens++| tool | what it did for this board |+|---|---|+| [Adom Hydrogen](https://wiki.adom.inc/adom/hydrogen) | The workspace: the AI (Claude Code here, or Codex and others) on the left, webviews for dashboards and wiki pages on the right, and a Linux workspace for the tools. |+| [Adom Bridge](https://wiki.adom.inc/adom/adom-bridge) | Lets the AI drive desktop apps on your PC: KiCad, LTspice and PSpice for TI, plus screen and window recording. |+| [Adom KiCad Bridge](https://wiki.adom.inc/adom/kicad-bridge) | Drives KiCad 10 live: placement, routing, pours, net highlights and silkscreen, each checked against KiCad's design rules. |++## Designing the board++| tool | what it did for this board |+|---|---|+| [adom-aiflow](https://wiki.adom.inc/adom/adom-aiflow) | Ran the board flow step by step: circuit, simulation, layout, copper pours, analysis, the rework loop and the molecule format. It also records a clip of every step. |+| [Chip Fetcher](https://wiki.adom.inc/adom/adom-chip-fetcher) | Gathered the datasheet and part data for the TPS54202. |+| [Adom Parts Search](https://wiki.adom.inc/adom/adom-parts-search) | Searched Mouser, DigiKey and JLCPCB at once to find in-stock parts. |+| [Adom Basic Parts](https://wiki.adom.inc/adom/adom-basic-parts) | The commodity passives and LEDs Adom stocks on reels, picked first for this board. |+| [Adom SPICE](https://wiki.adom.inc/adom/adom-spice-skillpack) | Ran and compared ngspice, LTspice and PSpice for TI on one dashboard. |+| [Adom Fields](https://wiki.adom.inc/adom/adom-fields) | Solved current density and heat on the real copper, found the choke point at the SW node, and checked the fix. |++## Symbols, footprints and 3D models++| tool | what it did for this board |+|---|---|+| [adom-symbol](https://wiki.adom.inc/adom/adom-symbol) | Made the schematic symbols, with the 3D chip outlines on U1, C1, L1 and D1. |+| [Adom Library](https://wiki.adom.inc/adom/adom-lbr) | Builds and translates part libraries for KiCad, Fusion 360 and Altium. |+| [Adom Footprint](https://wiki.adom.inc/adom/adom-footprint) | Footprint creation and checking. |+| [Adom Step2GLB](https://wiki.adom.inc/adom/adom-step2glb) | Adom's OpenCascade service for STEP files: checked every 3D model, drew the chip outlines, and made the board's 3D model. |+| [Adom Chip Laser](https://wiki.adom.inc/adom/adom-chip-laser) | Put each part number on its 3D model as a flat laser mark. |++## Sharing it++| tool | what it did for this board |+|---|---|+| [Adom Wiki](https://wiki.adom.inc/) | Hosts this project and a page for every part on the board, so anyone can reuse them. |+| [Component Widgets](https://wiki.adom.inc/adom/component-widgets) | The pinout and chip-outline widgets on the part pages. |+| [adom-video-post](https://wiki.adom.inc/adom/adom-video-post) | Clip-by-clip review for the [video](process-video.md). |