eda-architect

EDA Architect Skill

Define the architecture and constraints for electronics projects.

Auto-Activation Triggers

This skill activates when:

• User asks to "design a board", "create a project", "start a new PCB"
• User asks "what do I need for..." an electronics project
• Project has no docs/project-spec.md or docs/design-constraints.json
• User mentions requirements gathering or project planning

Context Requirements

Requires: Nothing (this is the first step)

Produces:

• docs/project-spec.md - Human-readable specification
• docs/design-constraints.json - Machine-readable constraints

Workflow

1. Understand the Project Goal

Ask the user about:

• What is this device/board intended to do?
• Target use case (prototype, production, hobby)?
• Any existing designs to reference?

2. Define Power Architecture

Determine:

• Input power source (USB, battery, mains, PoE, solar)
• Voltage rails needed (3.3V, 5V, 12V, etc.)
• Power topology per rail: LDO vs buck converter
  • See reference/POWER-TOPOLOGY-DECISION.md for decision tree
• Estimated power budget
• Battery life requirements if applicable

2.5 Thermal Budget

Estimate early:

• Total power dissipation (sum of all consumers)
• Hot components (any >0.5W needs attention)
• Cooling strategy: natural, forced, heatsink
• See reference/THERMAL-BUDGET.md for estimation guide

3. Processing Requirements

Establish:

• MCU/processor needs (or if needed at all)
• Processing requirements (speed, peripherals)
• Memory requirements (Flash, RAM)
• Preferred families (STM32, ESP32, RP2040, etc.)

4. Connectivity & Interfaces

Document:

• Wireless: WiFi, Bluetooth, LoRa, Zigbee, cellular
• Wired: Ethernet, USB, CAN, RS485, RS232
• User interfaces: buttons, LEDs, displays
• Debug/programming interfaces

4.5 Stackup Decision

Determine layer count based on complexity:

• 2-layer: Simple, LDO only, low-speed (I2C/SPI)
• 4-layer: MCU with switching regulator, USB, Ethernet, WiFi
• 6-layer: High-speed (>100MHz), DDR, dense routing
• See reference/LAYER-COUNT-DECISION.md for decision tree

5. Sensors & I/O

List:

• Required sensors
• Analog inputs/outputs
• Digital I/O requirements
• Any specialized interfaces (motor control, etc.)

6. Physical Constraints

Define:

• Target board dimensions
• Enclosure requirements
• Mounting hole positions
• Connector placement constraints
• Height restrictions

7. Environmental

Note:

• Operating temperature range
• Indoor/outdoor use
• IP rating if applicable

8. Manufacturing Targets

Capture:

• Target quantity
• Assembly method (hand, reflow, turnkey)
• Layer count preference
• Budget constraints

8.5 DFM Early Constraints

Capture manufacturer capabilities:

• Preferred manufacturer (JLCPCB, PCBWay, OSHPark)
• Assembly method constraints
• Fine-pitch components (affects hand soldering)
• Budget tier: prototype, low-volume, production

Output Format

project-spec.md Structure

# Project Specification: [Name]

## Overview
[Brief description and goals]

## Requirements Summary
| Category | Requirement |
|----------|-------------|
| Power Input | ... |
| Voltage Rails | ... |
| MCU | ... |
| Connectivity | ... |

## Detailed Requirements
[Sections for each category with full details]

## Constraints
[Physical, environmental, budget constraints]

## Open Questions
[Any unresolved items]

design-constraints.json Schema

See reference/CONSTRAINT-SCHEMA.md for full schema documentation.

Guidelines

• Ask clarifying questions rather than assuming
• Suggest common solutions when user is unsure
• Flag potential issues early (power budget, space constraints)
• Keep the spec focused - avoid scope creep
• Document rationale for key decisions
• Use project templates from reference/PROJECT-TEMPLATES.md as starting points

Architecture Validation Warnings

Before completing the architecture phase, check for these risky combinations:

Condition	Warning
2-layer + switching regulator	"Consider 4-layer - switching regulators need solid ground plane"
2-layer + USB/Ethernet	"Controlled impedance difficult on 2-layer - consider 4-layer"
>2W total + no thermal plan	"Add thermal budget - high power needs planning"
Hand assembly + fine-pitch (<0.5mm)	"Verify solderability - fine-pitch is difficult to hand solder"
>0.5W component + no thermal strategy	"Component dissipating >0.5W needs thermal attention"
Battery + LDO with high Vin-Vout	"Consider buck converter for battery life"

When a warning condition is detected, present it to the user and ask if they want to:

1. Update the design to address it
2. Acknowledge the risk and proceed

Next Steps

After completing architecture, suggest:

1. /eda-source [component-role] to begin component selection
2. Start with critical components: MCU, power regulators