EDA Research Skill

Source and select components for electronics projects.

Auto-Activation Triggers

This skill activates when:

• •User asks to "find a component", "search for", "source"
• •User asks about component specifications or comparisons
• •User mentions LCSC, datasheets, or part numbers
• •User asks "what MCU/regulator/sensor should I use"
• •Project has design-constraints.json but missing component selections

Context Requirements

Requires:

• •docs/design-constraints.json (or prompt user for requirements)
• •docs/project-spec.md (optional, for context)

Produces:

• •docs/component-selections.md - Human-readable selection log
• •docs/bom-draft.json - Machine-readable BOM
• •datasheets/*.pdf - Downloaded datasheets for selected components

Workflow

1. Load Context

Read existing project constraints:

@docs/design-constraints.json
@docs/project-spec.md
@docs/component-selections.md (if exists)

If constraints missing, ask user for minimum requirements:

• •What does this component need to do?
• •Key specifications (voltage, current, package)?
• •Budget constraints?

2. Understand Requirements

For the target component role, identify:

• •Critical specifications (must-have)
• •Preferred specifications (nice-to-have)
• •Package preferences (SMD size, through-hole)
• •Any specific brands or series to consider/avoid

2.5 Check Architecture Constraints

Before searching, review design-constraints.json for:

• •Power topology: LDO vs buck decision already made in architect phase
• •Thermal budget: Max watts for this role (check thermal.hotComponents)
• •DFM targets: Assembly method affects package choice
• •Board layers: May affect component density

For power components, see reference/REGULATOR-SELECTION.md for selection criteria. For passives, see reference/PASSIVE-SELECTION.md and reference/DECOUPLING-STRATEGY.md.

3. Research Options

Use web search to understand:

• •Common solutions for this application
• •Recommended parts from reference designs
• •Known issues or considerations
• •Alternative approaches

4. Search JLC

Use mcp__jlc__component_search to find candidates:

• •Search with specific parameters
• •Filter by stock availability
• •Note pricing at target quantity
• •Check for "Basic" parts (lower assembly fee at JLCPCB)

5. Analyze Candidates

For top 3-5 options:

• •Download/fetch datasheets
• •Extract key specifications
• •Check application circuits
• •Note layout requirements
• •Identify any gotchas

5.5 Validate Against Constraints

Before presenting options, verify each candidate:

Thermal validation:

P_dissipation = (calculated from datasheet)
Thermal budget = (from design-constraints.json)
✓ P_dissipation < Thermal budget

Assembly compatibility:

• •Hand assembly → 0603/0805 minimum, no fine-pitch
• •Reflow → 0402+ OK
• •Turnkey → Check JLCPCB availability

Architecture compliance:

• •Meets LDO/buck decision from architect phase
• •Noise specs OK for rail type (analog vs digital)
• •Efficiency acceptable for battery applications

Flag any candidates that fail validation with specific concerns.

6. Present Comparison

Create a comparison table:

Include recommendation with rationale.

7. Confirm Selection

• •Get user confirmation
• •Document selection with rationale
• •Update constraint file
• •Save datasheet

8. Validate Symbol (After library_fetch)

When fetching online components with mcp__jlc__library_fetch, analyze the returned validation_data:

Quick checks:

Common issues:

• •QFN/BGA packages often have exposed thermal pads (EP) not included in symbol
• •Pin electrical types may be incorrect (power pins marked as passive)
• •Pin names may not match datasheet

Fixing with library_fix:

Use mcp__jlc__library_fix to regenerate symbol with corrections:

mcp__jlc__library_fix lcsc_id="C#####" corrections='{
  "pins": [
    { "action": "add", "number": "EP", "name": "GND", "type": "passive" },
    { "action": "modify", "number": "1", "set_type": "power_in" }
  ]
}'

Correction actions:

• •add - Add missing pin (number, name, type required)
• •modify - Rename and/or change electrical type
• •swap - Swap positions of two pins
• •remove - Remove incorrect pin

Output Format

component-selections.md Entry

### [Role]: [Part Name] ([LCSC Number])

**Selected:** [Date]
**MPN:** [Manufacturer Part Number]
**Manufacturer:** [Name]
**Price:** $X.XX @ [quantity]

**Specifications:**
- Key spec 1: value
- Key spec 2: value

**Rationale:**
[Why this part was chosen over alternatives]

**Alternatives Considered:**
- [Part 2] - rejected because [reason]
- [Part 3] - rejected because [reason]

**Design Notes:**
- [Any layout or application notes from datasheet]

**Datasheet:** `datasheets/[filename].pdf`

bom-draft.json Entry

{
  "role": "regulator-3v3",
  "lcsc": "C6186",
  "mpn": "AMS1117-3.3",
  "manufacturer": "AMS",
  "description": "3.3V 1A LDO Regulator",
  "value": "3.3V",
  "footprint": "SOT-223",
  "quantity": 1,
  "unitPrice": 0.04,
  "extendedPrice": 0.04,
  "category": "power",
  "basic": true
}

Component Role Categories

See reference/COMPONENT-CATEGORIES.md for detailed role definitions.

Common roles:

• •mcu - Main microcontroller
• •regulator-Xv - Voltage regulators
• •crystal - Oscillators/crystals
• •connector-* - Various connectors
• •esd-* - ESD protection
• •decoupling-* - Bypass/bulk capacitors
• •led-* - Indicator LEDs
• •sensor-* - Various sensors

Guidelines

• •Prefer JLCPCB "Basic" parts when suitable (lower assembly cost)
• •Check stock levels - avoid parts with < 100 in stock
• •Consider package size vs hand soldering capability
• •Note lead times for non-stock items
• •Always document why a part was chosen
• •Download datasheets for all selected components
• •Identify 1-2 alternatives for critical components (see reference/COMPONENT-ALTERNATIVES.md)
• •Validate thermal before confirming power components
• •Check architecture decisions from design-constraints.json before selecting

Reference Documents

Next Steps

After component selection is complete:

1. •Run /eda-source for remaining components
2. •When all components selected, run /eda-schematic
3. •Update design-constraints.json stage to "schematic"