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:

Part MPN Key Specs Price Stock Pros Cons

... ... ... ... ... ... ...

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:

Check Expected Action if Failed

pin_pad_count_match

true

Check for exposed pads (EP)

has_power_pins

true (for ICs) Review pin types

has_ground_pins

true (for ICs) Review pin names

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

Document Use For

REGULATOR-SELECTION.md

LDO vs Buck selection criteria

DECOUPLING-STRATEGY.md

Capacitor values for ICs

PASSIVE-SELECTION.md

Resistor/capacitor fundamentals

COMPONENT-ALTERNATIVES.md

Finding equivalent parts

DATASHEET-ANALYSIS.md

Extracting key specs

COMPONENT-CATEGORIES.md

Role naming conventions

JLC-SEARCH-TIPS.md

Search strategies

Next Steps

After component selection is complete:

• Run /eda-source for remaining components

• When all components selected, run /eda-schematic

• Update design-constraints.json stage to "schematic"