ESP32 PCB Layout and Routing Tutorial

Overview

This tutorial covers designing a complete ESP32 development board using tscircuit. You'll learn professional PCB layout techniques including component placement, power trace routing, USB differential pairs, crystal oscillator placement, and antenna keepout zones.

Project Specifications

Parameter	Value
Board Size	30mm × 60mm
Layers	2-layer (Top/Bottom)
Target	ESP32-WROOM-32 development board
USB	USB-C for programming and power
Voltage Regulator	5V to 3.3V LDO (AMS1117-3.3)
Programming	Auto-reset via DTR/RTS from USB-UART

Components

Ref	Part	Description	Footprint
U1	ESP32-WROOM-32	Dual-core MCU with WiFi/BT	`esp32-wroom-32`
J1	USB-C Receptacle	USB Type-C for power/programming	`smd-usb-c`
U2	CH340G	USB-to-Serial bridge	`sop-16`
U3	AMS1117-3.3	3.3V LDO regulator	`sot-223`
Y1	32.768 kHz Crystal	RTC clock oscillator	`3215_smd`
Y2	40 MHz Crystal	Main MCU oscillator	`2520_smd`
C1-C4	Decoupling caps	100nF ceramic capacitors	`0402`
R1-R6	Pull-up/pull-down	10kΩ resistors	`0402`
LED1	Power indicator	Green status LED	`0603`
LED2	TX indicator	Yellow activity LED	`0603`
SW1	Reset button	Tactile push button	`pushbutton`
SW2	Boot button	Tactile push button	`pushbutton`

Step 1: Power Architecture

The ESP32 requires a stable 3.3V supply. We use an AMS1117-3.3 LDO regulator:

<capacitor name="C_IN" footprint="0805" capacitance="10uF" />
<capacitor name="C_OUT" footprint="0805" capacitance="10uF" />

<chip name="U3" footprint="sot-223" />

<trace from="U3 .vin" to="net.5V" />
<trace from="U3 .gnd" to="net.GND" />
<trace from="U3 .vout" to="net.3V3" />

Decoupling Capacitors

Each power pin on the ESP32 needs a 100nF decoupling capacitor placed as close as possible:

<capacitor name="C1" footprint="0402" capacitance="100nF" pcbX={-8} pcbY={-5} />
<capacitor name="C2" footprint="0402" capacitance="100nF" pcbX={-5} pcbY={-5} />
<capacitor name="C3" footprint="0402" capacitance="100nF" pcbX={-2} pcbY={-5} />
<capacitor name="C4" footprint="0402" capacitance="100nF" pcbX={1} pcbY={-5} />

Rule of thumb: Place decoupling caps within 2mm of the power pin they're decoupling.

Step 2: ESP32 Module Placement

The ESP32-WROOM-32 should be placed with the antenna overhanging the board edge for optimal WiFi performance:

<chip
  name="U1"
  footprint="esp32-wroom-32"
  pcbX={10}
  pcbY={0}
  pcbRotation={0}
/>

Critical Placement rules:

Antenna keepout: No copper pour within 15mm of the antenna area
Ground plane: Solid ground plane under the module
Crystal proximity: Place 40MHz crystal within 5mm of OSC pins
Flash memory: Keep high-speed signals away from the antenna side

Step 3: USB-C and CH340G Circuit

The CH340G provides USB-to-serial conversion for programming:

import { SmdUsbC } from "@tsci/seveibar.smd-usb-c"

<SmdUsbC
  name="J1"
  connections={{
    GND1: "net.GND",
    GND2: "net.GND",
    VBUS1: "net.5V",
    VBUS2: "net.5V",
    D1: ".U2 > .d-",
    D2: ".U2 > .d+",
  }}
  pcbX={-25}
  pcbY={0}
/>

<chip
  name="U2"
  footprint="sop-16"
  pcbX={-15}
  pcbY={0}
/>

Auto-Reset Circuit

The ESP32 needs an auto-reset circuit for programming. Connect CH340G DTR and RTS to ESP32 EN and GPIO0:

<capacitor name="C_DTR" footprint="0402" capacitance="100nF" />
<resistor name="R_DTR" footprint="0402" resistance="1k" />

<trace from=".U2 .dtr" to=".C_DTR .pos" />
<trace from=".C_DTR .neg" to=".U1 > .EN" />
<trace from=".U2 .rts" to=".R_DTR .pos" />
<trace from=".R_DTR .neg" to=".U1 > .GPIO0" />

Step 4: Crystal Oscillators

40 MHz Main Crystal

<crystal
  name="Y2"
  footprint="2520_smd"
  frequency="40MHz"
  loadCapacitance="12pF"
  pcbX={5}
  pcbY={-8}
/>

<capacitor name="C_Y2A" footprint="0402" capacitance="12pF" pcbX={4} pcbY={-9} />
<capacitor name="C_Y2B" footprint="0402" capacitance="12pF" pcbX={6} pcbY={-9} />

<trace from=".Y2 .1" to=".C_Y2A .pos" />
<trace from=".Y2 .2" to=".C_Y2B .pos" />
<trace from=".C_Y2A .neg" to="net.GND" />
<trace from=".C_Y2B .neg" to="net.GND" />

32.768 kHz RTC Crystal

<crystal
  name="Y1"
  footprint="3215_smd"
  frequency="32.768kHz"
  pcbX={5}
  pcbY={8}
/>

<capacitor name="C_Y1A" footprint="0402" capacitance="6.8pF" />
<capacitor name="C_Y1B" footprint="0402" capacitance="6.8pF" />

Step 5: LED Indicators

<led name="LED1" color="green" footprint="0603" pcbX={-20} pcbY={-10} />
<resistor name="R_LED1" footprint="0402" resistance="330" pcbX={-22} pcbY={-10} />

<trace from="net.3V3" to=".R_LED1 .pos" />
<trace from=".R_LED1 .neg" to=".LED1 .pos" />
<trace from=".LED1 .neg" to="net.GND" />

Step 6: Reset and Boot Buttons

<pushbutton name="SW1" footprint="pushbutton" pcbX={-20} pcbY={10} />
<pushbutton name="SW2" footprint="pushbutton" pcbX={-15} pcbY={10} />

<trace from=".SW1 .pin1" to="net.GND" />
<trace from=".SW1 .pin2" to=".U1 > .EN" />

<trace from=".SW2 .pin1" to="net.GND" />
<trace from=".SW2 .pin2" to=".U1 > .GPIO0" />

Complete Circuit

import { SmdUsbC } from "@tsci/seveibar.smd-usb-c"

export default () => {
  return (
    <board width="60mm" height="30mm">
      {/* ESP32 Module */}
      <chip name="U1" footprint="esp32-wroom-32" pcbX={10} pcbY={0} />
      
      {/* USB-C Connector */}
      <SmdUsbC
        name="J1"
        connections={{
          GND1: "net.GND",
          GND2: "net.GND",
          VBUS1: "net.5V",
          VBUS2: "net.5V",
        }}
        pcbX={-25}
        pcbY={0}
      />
      
      {/* CH340G USB-UART */}
      <chip name="U2" footprint="sop-16" pcbX={-15} pcbY={0} />
      
      {/* AMS1117-3.3 Voltage Regulator */}
      <chip name="U3" footprint="sot-223" pcbX={-10} pcbY={-10} />
      
      {/* Power LED */}
      <led name="LED1" color="green" footprint="0603" pcbX={-20} pcbY={-10} />
      <resistor name="R_LED1" footprint="0402" resistance="330" pcbX={-22} pcbY={-10} />
      
      {/* Reset Button */}
      <pushbutton name="SW1" footprint="pushbutton" pcbX={-20} pcbY={10} />
      
      {/* Boot Button */}
      <pushbutton name="SW2" footprint="pushbutton" pcbX={-15} pcbY={10} />
      
      {/* 40 MHz Crystal */}
      <crystal name="Y2" footprint="2520_smd" frequency="40MHz" pcbX={5} pcbY={-8} />
      
      {/* 32.768 kHz Crystal */}
      <crystal name="Y1" footprint="3215_smd" frequency="32.768kHz" pcbX={5} pcbY={8} />
      
      {/* Decoupling Capacitors */}
      <capacitor name="C1" footprint="0402" capacitance="100nF" pcbX={-8} pcbY={-5} />
      <capacitor name="C2" footprint="0402" capacitance="100nF" pcbX={-5} pcbY={-5} />
      <capacitor name="C3" footprint="0402" capacitance="100nF" pcbX={-2} pcbY={-5} />
      <capacitor name="C4" footprint="0402" capacitance="100nF" pcbX={1} pcbY={-5} />
    </board>
  )
}

PCB Layout Rules

Power Traces

5V input: Minimum 0.5mm trace width (500mA current)
3.3V output: Minimum 0.3mm trace width (ESP32 peak ~500mA)
GND plane: Use a solid ground plane on the bottom layer

Signal Traces

UART (TX/RX): 0.2mm traces, keep short
SPI: 0.2mm traces, controlled impedance not needed at ESP32 speeds
I2C: 0.2mm traces with 4.7kΩ pull-ups

USB Differential Pair

D+/D-: Route as differential pair with 90Ω impedance
Length matching: Keep length difference under 5mm
Ground reference: Solid ground plane underneath

Antenna Guidelines

Keepout zone: 15mm no-copper zone around antenna
No vias: No vias under or near the antenna
Ground plane: Cut out ground plane in antenna area

Manufacturing Files

# Generate Gerbers
tsci build --gerber

# Generate BOM
tsci build --bom

# Generate Assembly
tsci build --pick-and-place

Cost Estimate

Component	Unit Cost	Qty	Total
ESP32-WROOM-32	$2.50	1	$2.50
CH340G	$0.30	1	$0.30
AMS1117-3.3	$0.15	1	$0.15
USB-C Receptacle	$0.15	1	$0.15
Crystals (×2)	$0.20	2	$0.40
Passives (×20)	$0.01	20	$0.20
PCB (2-layer)	$1.00	1	$1.00
Total			$4.70

Summary

You've designed a complete ESP32 development board covering:

Power architecture with LDO regulation
USB-C connectivity with CH340G programming
Auto-reset circuit for seamless flashing
Crystal oscillators for MCU timing
PCB layout rules for WiFi performance
Manufacturing file generation

This board is ready for production and can be manufactured at any standard PCB fab house.

Overview​

Project Specifications​

Components​

Step 1: Power Architecture​

Decoupling Capacitors​

Step 2: ESP32 Module Placement​

Critical Placement rules:​

Step 3: USB-C and CH340G Circuit​

Auto-Reset Circuit​

Step 4: Crystal Oscillators​

40 MHz Main Crystal​

32.768 kHz RTC Crystal​

Step 5: LED Indicators​

Step 6: Reset and Boot Buttons​

Complete Circuit​

PCB Layout Rules​

Power Traces​

Signal Traces​

USB Differential Pair​

Antenna Guidelines​

Manufacturing Files​

Cost Estimate​

Summary​