solvinn

/

All changes saved

0

0

Files

Schematic

PCB

Log InSign Up

ESP32 PPG Sensor Design

flux

0:08

Work done
  • Separated the charger programming path from output channel 1 by moving MCP73871 PROG1 onto dedicated resistor R8, while keeping channel output on R4.
  • Added optional USB-C power input using J2 with 5.1 kOhm CC pull-downs R6 and R7, plus input capacitors C11 and C12, and tied VIN_5V into charger U3.
  • Tied unused MCP73871 status/config pins on U3 to GND so they are no longer floating.
  • Cleaned net intent by creating output-side naming for channel 2 and preserving separate OUT1 and OUT2 current-limit paths through R4 and R5.
  • Defined the layout as an 80 mm x 80 mm rounded rectangle, set Standard 4 Layer stackup, and established baseline layout constraints including 0.15 mm minimum trace width, 0.2 mm keep out, 0.5 mm board inset margin, and preferred widths of 0.15 mm / 0.25 mm / 0.5 mm.
  • Applied explicit net trace-width rules for R8's PROG1 net and the OUT2 GPIO-side net.
Success criteria review
  • ✅ The charger programming resistor is now functionally separated from output channel 1.
  • ✅ The optional USB input/charge connector is added and integrated into the charging path.
  • ✅ The PCB layout now has a compact board size, 4-layer stackup, and baseline manufacturability constraints.
  • ✅ The charger-related ERC issues were reduced by grounding unused MCP73871 pins.
  • ✅ Remaining floating-pin ERC items are now limited to intentionally unused ESP32 module pins, unused USB-C data/SBU pins, unused TVS array I/O pins, and extra standalone GND symbols that were added earlier but are not needed for function.
Next steps The remaining ERC items are cleanup-level and not charger/function blockers. The main follow-up is to remove the unused standalone GND symbols, replace or rewire D1 to a simpler VBUS TVS part, and decide whether the unused ESP32 and USB data pins should stay intentionally unconnected or be terminated/documented. I can do that cleanup pass next.
Fix remaining ERCs
Set compact board size
Add USB charge input
33 days
​
Sign up to send

To get started, talk to Flux or create a New Document.

Reviews

Documents

    Documents are markdown text files which describe project goals, capture details, or even simulation outputs.

    Assets

    Assets are files uploaded to this project which can be used in various ways.

    ESP32 PPG Battery Device thumbnail
    Battery-powered ESP32-WROOM-32 design with MAX30102 PPG sensor, MCP73871 single-cell Li-ion charging and power-path management, 3.3V regulation, and two low-current output terminals.

    Properties

    V

    Pricing & Availability

    Distributor

    Qty 1

    Arrow

    $3.42–$4.07

    Digi-Key

    $12.93–$3,267.45

    LCSC

    $24.95

    Mouser

    $20.70

    TME

    $4.31

    Verical

    $3.41–$8.41

    Controls

    Welcome 👋

    Flux helps you build PCBs faster with an AI teammate!

    Create your account to collaborate, stay updated, fork your own version, and get instant answers from our AI agent.

        Introducing AI Placement!
        AI Placement Demo

        AI-Powered Component Placement

        Let AI place your components intelligently. AI Placement analyzes your schematic and positions components for optimal routing, signal integrity, and board density.

        From Schematic to Layout in Seconds

        Skip the tedious manual placement. AI Placement generates a starting layout you can refine, saving hours of repetitive work on every new design.

        Works With Auto-Layout

        Pair AI Placement with Auto-Layout for a complete AI-driven PCB design flow — from component placement through trace routing, all with one click.

        Try it