Pcb Designer

PCB Designer v2 — Full-Stack Hardware Design

Comprehensive PCB design guidance for embedded systems, IoT devices, mixed-signal designs, and sensor data-acquisition projects.

Covers the entire lifecycle: requirements → component selection → schematic design → PCB layout → signal integrity → thermal → manufacturing → compliance → production.

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Quick Start

cd ~/.claude/skills/
git clone  pcb-designer

Pairs with easyeda-api-skill for automated EDA control.

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Reference Index

| Scenario | Reference | |----------|-----------| | 立创 EDA / LCEDA workflow | references/lceda-workflow.md | | KiCad workflow | references/kicad-workflow.md | | DFM pre-export checklist | references/dfm-checklist.md | | 2-layer vs 4-layer decision | references/layer-choice.md | | EMC & signal integrity | references/emc-guidelines.md | | Power design (LDO/DC-DC/Battery) | references/power-design.md | | Analog & mixed-signal | references/analog-design.md | | RF & antenna design | references/rf-design.md | | High-speed digital | references/high-speed-digital.md | | Communication interfaces | references/communication-interfaces.md | | Thermal design | references/thermal-design.md | | Protection & reliability | references/protection-reliability.md | | Testing & debugging | references/testing-debug.md | | Compliance & certification | references/compliance-certification.md | | Manufacturing & production | references/manufacturing-production.md | | MCU platform references | references/mcu-platforms.md | | PCB materials & processes | references/pcb-materials.md | | Cost optimization | references/cost-optimization.md |

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1. Design Process

Standard Workflow

Requirements → Component Selection → Schematic Design →
  Schematic Review → PCB Layout → Routing →
  DFM Check → Export → Order

1.1 Requirements Clarification

Ask about:

• MCU / SoC: Model, package, pin count, frequency
• Peripherals: Sensors (SPI/I2C/UART/analog), displays, storage, radios, audio
• Power: Battery (chemistry, voltage, capacity), USB, PoE, solar, power budget
• Mechanical: Board size, mounting, enclosure, connector placement
• Environment: Temperature range, vibration, humidity, IP rating
• Compliance: FCC, CE, UL, automotive, medical
• Budget: BOM cost target, layer count, quantity (proto vs production)

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2. Component Selection

2.1 Supply Chain Strategy

| Priority | Source | Notes | |----------|--------|-------| | 1st | LCSC Basic Parts | No JLCPCB assembly surcharge | | 2nd | LCSC Extended | ¥3/part surcharge | | 3rd | Digi-Key / Mouser | Consigned to JLCPCB | | Last resort | Custom sourcing | Slow, logistics overhead |

2.2 Package Preference

| Density | Passives | ICs | Hand-solderable | |---------|----------|-----|:---:| | Ultra-compact | 0201 | WLCSP/BGA | ✗ | | High density | 0402 | QFN/LGA | ✗ | | Sweet spot | 0603 | QFN/QFP | ✓ (with practice) | | Low density | 0805 | SOIC/SOP | ✓ | | Through-hole | — | DIP | ✓ (easy) |

2.3 Common Components (LCSC)

| Function | Part | Package | LCSC # | |----------|------|---------|--------| | ESP32-S3 (PCB ant) | ESP32-S3-WROOM-1-N16R8 | Module | C2913201 | | ESP32-S3 (IPEX) | ESP32-S3-WROOM-1U-N16R8 | Module | C2913203 | | 3.3V LDO 1A | AMS1117-3.3 | SOT-223 | C6186 | | 3.3V LDO low-noise | ME6211C33M5G | SOT-23-5 | C82942 | | 3.3V Buck 2A | MT2492 | SOT-23-6 | — | | LiPo charger 1A | TP4056 | SOP-8 | C382139 | | USB-C 16P Female | TYPE-C-31-M-12 | SMD | C165948 | | TF Card Push-Push | 9P Push-Push | SMD | C112217 | | USB-UART | CH340X | MSOP-10 | — | | WS2812B RGB LED | WS2812B-B/W | 5050 | — | | 32.768kHz XTAL | 3215 12.5pF | SMD-3215 | C620155 | | ESD Protection | LESD5D5.0CT1G | SOD-523 | — |

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3. Schematic Review

Before layout, verify:

• [ ] Every VDD pin has 0.1µF decoupling within 5mm
• [ ] Bulk capacitance (10–47µF) on each power rail
• [ ] I2C: 4.7kΩ pull-ups on SDA+SCL (one pair per bus)
• [ ] SPI >20MHz: 22Ω series termination at source
• [ ] ESP32: EN pulled high (10kΩ+1µF RC), IO0 pulled high (10kΩ)
• [ ] Battery ADC divider: ≤3.3V at max battery voltage
• [ ] USB: ESD diodes at connector, not at MCU
• [ ] No floating inputs (unused CMOS inputs must be tied high or low)
• [ ] Programming/debug header accessible
• [ ] Test points: GND, 3V3, UART TX/RX minimum
• [ ] Pin conflicts resolved (no shared GPIO functions)
• [ ] Power sequencing correct (if multiple rails)

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4. PCB Layout

4.1 Stackup Decision

| Factor | 2-Layer | 4-Layer | 6+ Layer | |--------|---------|---------|----------| | Cost (50×50mm, 5pcs) | ~¥5 | ~¥30 | ~¥80+ | | Signal integrity | Fair | Good | Excellent | | EMI control | Hard | Good | Easy | | Suitable for | Slow MCU, proto | ESP32, production | DDR, RF dense |

Recommended 4-layer stackup (JLCPCB JLC7628):

L1: Signal + Components     ← Top
Prepreg (0.2mm)
L2: GND Plane (continuous)  ← Solid return path
Core (0.5mm)
L3: Power Plane (3.3V)      ← Low-Z distribution
Prepreg (0.2mm)
L4: Signal + GND fill       ← Bottom

4.2 Placement Order

1. Fixed items: connectors, mounting holes, antenna
2. MCU/module: center, antenna outward
3. Power: near input, away from sensitive analog
4. High-speed: closest to MCU, shortest paths
5. Sensors: near MCU, oriented for mechanical alignment
6. Passives: decoupling caps at IC pins (≤5mm)

4.3 Antenna Keep-Out (ESP32)

• 15mm × 15mm zone, ALL layers NO copper
• No components, traces, mounting holes, battery, or metal near it
• Antenna faces board edge OUTWARD

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5. Routing Rules

| Signal | Min Width | Min Spacing | Special | |--------|-----------|-------------|---------| | Digital ≤20MHz | 6mil | 6mil | — | | SPI 40MHz | 6mil | 18mil (3×W) | 22Ω series term, ±2mm match | | SPI 20MHz | 6mil | 12mil (2×W) | Pull-ups | | I2C 400kHz | 6mil | 12mil | Away from clocks | | I2C 1MHz (Fast+) | 6mil | 18mil | Shorter traces | | Power >100mA | 12mil | 12mil | Short | | Power >500mA | 20mil | 12mil | Very short | | Power >1A | Copper pour | 12mil | Multiple vias | | USB D+/D- | 6mil | 6mil | 90Ω diff, length-matched | | RF 50Ω | Calculated | — | Reference plane beneath | | Audio analog | 10mil | 20mil | Guard traces optional |

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6. Embedded Circuit Patterns

6.1 ESP32 Minimum Boot

3V3 ── 10kΩ ── EN ── 1µF ── GND
3V3 ── 10kΩ ── IO0 ── BUTTON ── GND

6.2 SPI Sensor Bus (40MHz, Star Topology)

MCU MOSI ── 22Ω ──┬── Sensor1 SDI
                   ├── Sensor2 SDI
                   └── Sensor3 SDI
MCU SCLK ── 22Ω ──┬── Sensor1 SCK
                   ├── Sensor2 SCK
                   └── Sensor3 SCK
MCU MISO ──┬─────── Sensor1 SDO
            ├─────── Sensor2 SDO
            └─────── Sensor3 SDO
Each sensor: dedicated CS line (no resistor needed)

6.3 I2C Bus

3V3 ── 4.7kΩ ──┬── SDA
               └── All devices SDA
3V3 ── 4.7kΩ ──┬── SCL
               └── All devices SCL

6.4 LiPo Charger (TP4056)

USB 5V ──┬── TP4056 VCC(pin4,8)
          ├── PROG(pin2) ── Rprog ── GND    (I=1000/Rprog)
          ├── BAT(pin5) ── BAT+
          ├── CHRG(pin6) ── LED_RED ── 2kΩ ── 5V
          ├── STDBY(pin7) ── LED_GREEN ── 2kΩ ── 5V
          └── 10µF caps on input & output

6.5 DC-DC Buck (MT2492 → 3.3V)

SYS_5V ── 10µF ── VIN(pin5)
EN(pin4) ── 10kΩ ── SYS_5V
SW(pin6) ── L(4.7µH) ──┬── 3V3 + 22µF output cap
                        FB(pin3) ──┬── R1(100kΩ) ── 3V3
                                   └── R2(22.1kΩ) ── GND
Vout = 0.6 × (1 + R1/R2)

6.6 USB-C with ESD

VBUS ── Schottky ── CHARGE_5V
CC1 ── 5.1kΩ ── GND
CC2 ── 5.1kΩ ── GND
D+ ── ESD ── GND ──┬── CH340X/GPIO
D- ── ESD ── GND ──┘

6.7 NPN Buzzer Driver

VCC ── BUZZER ── NPN_C
GPIO ── 1kΩ ── NPN_B
        10kΩ ── NPN_B ── GND (anti-float)
NPN_E ── GND
1N4148: cathode to VCC, anode to NPN_C (flyback)

6.8 Battery Voltage ADC

BAT+ ── R1(20kΩ) ──┬── GPIO_ADC ── 0.1µF ── GND
                   R2(30kΩ)
                   GND
Ratio: 30/(20+30)=0.6 → 4.2V→2.52V at ADC

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7. DFM Checks

Full checklist at references/dfm-checklist.md. Quick checks:

Minimum Fab Capability (JLCPCB)

| Parameter | Min | Recommended | |-----------|-----|-------------| | Trace/space | 3.5mil | 6mil | | Via hole | 0.2mm | 0.3mm | | Via pad | 0.45mm | 0.6mm | | Annular ring | 0.125mm | 0.15mm |

Pre-Export

• [ ] 0 DRC errors
• [ ] Board outline on mechanical layer
• [ ] Silkscreen ≥0.8mm height, not on pads
• [ ] No acute angles in copper
• [ ] Thermal relief on pads to pours
• [ ] No isolated copper islands
• [ ] All nets routed (no ratsnest)

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8. EMC & Signal Integrity

See references/emc-guidelines.md for full details.

Key Rules

1. Return paths: never cut L2 GND plane with long traces
2. Decoupling: 0.1µF per VDD pin, ≤5mm from pin, short loop
3. Termination: 22Ω at source for high-speed SPI
4. Spacing: SPI 3×W from other signals, I2C away from clocks
5. Stitching: GND vias every 5–10mm along edges

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9. EDA Tool Workflows

立创 EDA Pro (Primary)

See references/lceda-workflow.md.

• File → Export → Gerber (RS-274X, mm)
• File → Export → BOM (CSV)
• File → Export → Pick & Place

KiCad 8.x (Alternative)

See references/kicad-workflow.md.

• Git-friendly text format, excellent 3D viewer

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10. Design Review

Three-tier evaluation:

• 🔴 Critical: prevents manufacturing or causes failure
• 🟡 Warning: yield or reliability risk
• 🔵 Suggestion: performance, cost, or ease-of-assembly improvement

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11. Power Design

See references/power-design.md.

LDO Selection

• Dropout voltage: Vin_min - Vout Vout | Low | Medium |

| Boost | Vin Vout | Minimal | Low (best PSRR) |

Battery Management

• 1S LiPo (3.7V): TP4056 charger, DW01+FS8205 protection
• 2S-4S: BQ-series charger + cell balancing
• Fuel gauge: MAX17048 (I2C), BQ27427
• Solar: CN3791 (MPPT), BQ24210

Power Sequencing

• Ensure core voltage before I/O voltage
• Use RC delays or dedicated sequencer ICs
• Check MCU datasheet for power-up requirements

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12. MCU Platforms

See references/mcu-platforms.md.

Platform Selection Guide

| Platform | Best For | Max Clock | Wireless | Eco-system | |----------|----------|:---------:|:--------:|:----------:| | ESP32-S3 | IoT, WiFi/BLE | 240MHz | ✓ | Arduino, ESP-IDF | | STM32F4 | Industrial, DSP | 180MHz | ✗ | STM32Cube, HAL | | STM32H7 | High-perf, GUI | 550MHz | ✗ | STM32Cube | | nRF52840 | BLE, Thread | 64MHz | ✓ | nRF Connect, Zephyr | | nRF54L15 | Next-gen BLE | 128MHz | ✓ | Zephyr | | RP2040 | Low-cost, PIO | 133MHz | ✗ | Pico SDK, Arduino | | RP2350 | Secure, RISC-V | 150MHz | ✗ | Pico SDK | | CH32V203 | RISC-V budget | 144MHz | ✗ | MounRiver | | ATmega328P | Simple, 5V | 16MHz | ✗ | Arduino | | CH582 | BLE budget | 60MHz | ✓ | MounRiver |

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13. Communication Interfaces

See references/communication-interfaces.md.

| Interface | Speed | Topology | Key Rules | |-----------|-------|----------|-----------| | UART | ≤3Mbps | Point-to-point | Cross TX/RX | | I2C | 100k/400k/1M | Multi-drop bus | Pull-ups, ≤400pF | | SPI | ≤50MHz | Star, multi-CS | 22Ω term, ±2mm match | | QSPI/OSPI | ≤133MHz | Point-to-point | Length match all data lines | | CAN | ≤1Mbps | Differential bus | 120Ω term both ends | | RS-485 | ≤50Mbps | Differential multi-drop | 120Ω term, fail-safe bias | | USB 2.0 FS | 12Mbps | Point-to-point | 90Ω diff, ESD at conn | | USB 2.0 HS | 480Mbps | Point-to-point | 90Ω diff, impedance critical | | Ethernet 100M | 100Mbps | Point-to-point | RMII, magnetics, 50Ω | | SDIO | ≤208MHz | Point-to-point | Length match, pull-ups | | I2S | Variable | Point-to-point | Separate MCLK/BCLK/LRCK | | LVDS/MIPI | ≤1.5Gbps/lane | Diff pair | 100Ω diff, tight matching |

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14. Analog & Mixed-Signal

See references/analog-design.md.

Op-Amp Selection

• GBW ≥ 10× signal frequency for buffer, ≥ 100× for gain stages
• Slew rate ≥ 2π × f × Vpeak
• Input offset: 5Gbps

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17. PCB Materials & Processes

See references/pcb-materials.md.

Substrate

| Material | εr | Tan δ | Tg | Cost | Use | |----------|:---:|:---:|:---:|------|-----| | FR-4 (standard) | 4.2-4.6 | 0.02 | 130°C | ¥ | Digital, low-freq | | FR-4 (high-Tg) | 4.2-4.6 | 0.02 | 170°C | ¥¥ | Lead-free, automotive | | Rogers 4350B | 3.48 | 0.004 | 280°C | ¥¥¥¥ | RF/microwave | | Isola 370HR | 3.9 | 0.01 | 180°C | ¥¥¥ | High-speed digital |

Surface Finish

| Finish | Shelf Life | Flatness | Cost | Lead-free | |--------|:---:|:---:|------|:---:| | HASL (有铅) | 12mo | Poor | ¥ | ✗ | | HASL (无铅) | 12mo | Poor | ¥ | ✓ | | ENIG | 12mo | Excellent | ¥¥ | ✓ | | ENEPIG | 12mo | Excellent | ¥¥¥ | ✓ | | OSP | 6mo | Excellent | ¥ | ✓ | | Immersion Silver | 6mo | Good | ¥¥ | ✓ |

Advanced Processes

• Blind via: L1→L2 or L3→L4 (outer to inner)
• Buried via: L2→L3 (inner to inner)
• Microvia: 0.5W in one location)

Thermal Resistance

• θJA: junction-to-ambient (from datasheet)
• θJC: junction-to-case (for heatsink design)
• Tj = Ta + Pd × θJA → must stay 10kV | AC/pulse | ¥¥ |

| Capacitive | 5kV | ≤150Mbps | ¥¥ |

IPC Reliability Standards

• IPC-2221: Generic design standard
• IPC-6012: Rigid PCB qualification
• IPC-A-610: Acceptability of electronic assemblies
• J-STD-001: Soldering requirements
• IPC-7351: Land pattern standard

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20. Testing & Debugging

See references/testing-debug.md.

Test Points

• Minimum: GND, 3V3, UART TX, UART RX
• Recommended: all power rails, key signals, unused GPIOs
• Pad size: ≥1.0mm for pogo pin, ≥1.5mm for multimeter probe
• Keep test points on one side (usually bottom) for test fixture

Debug Interfaces

| Interface | Pins | Use | |-----------|:---:|-----| | SWD (ARM) | SWCLK+SWDIO+GND | Programming + debug | | JTAG | TMS+TDI+TDO+TCK+GND | Boundary scan | | cJTAG (2-wire) | Same as SWD | ARM debug alternative | | UART | TX+RX+GND | Serial console, log output |

Production Test

• ICT (In-Circuit Test): bed-of-nails, checks component values
• Flying probe: no fixture, slower, good for prototypes
• Functional test: power up, run self-test firmware
• Programming: pre-program MCUs or ISP on-board

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21. Cost Optimization

See references/cost-optimization.md for full analysis.

Quick Wins

• LCSC Basic Parts: save ¥3/part vs extended library
• Consolidate values: fewer unique resistor/capacitor values
• ≤100×100mm: JLCPCB's cheapest PCB tier
• V-cut over router for rectangular panels
• Single-sided SMT if possible (2× setup cost for double-sided)

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22. Compliance & Certification

See references/compliance-certification.md.

Key Certifications

| Certification | Region | Scope | Est. Cost | |---------------|--------|-------|:---:| | FCC Part 15 | US | Intentional/unintentional radiator | $3k-15k | | CE (RED) | EU | Radio Equipment Directive | €5k-20k | | UKCA | UK | Post-Brexit equivalent of CE | £3k-15k | | RoHS | EU/Global | Hazardous substance restriction | $500-2k | | REACH | EU | Chemical substance registration | Compliance declaration | | UL | US/Global | Safety certification | $5k-50k | | AEC-Q100 | Global | Automotive IC qualification | IC-level only |

Pre-Compliance Testing

• Rent EMC chamber (~$200/hr) before formal testing
• Use near-field probes + spectrum analyzer for in-house pre-scan
• Common failure points: power supply noise, unshielded cables, poor grounding

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23. Manufacturing & Production

See references/manufacturing-production.md.

Stencil Design

• Thickness: 0.1mm (fine pitch) to 0.15mm (standard)
• Aperture: 1:1 for chips, reduce 10-20% for passives
• Electropolished: for fine pitch (217°C: Liquidus, 60-90s

Peak: 235°C─250°C, 10-30s Cooling: pcb-designer git clone easyeda-api-skill-main

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [SPREsxm](https://github.com/SPREsxm)
- **Source:** [SPREsxm/claude-pcb-designer](https://github.com/SPREsxm/claude-pcb-designer)
- **License:** MIT

Install and usage instructions live in the source repository linked above.