ESP32-S3 Firmware Refinement

flux

Routing started and completed a main pass:
  • Added 199 routing nodes.
  • Renamed switches to RST_SW and BOOT_SW.
  • Fixed the 12V regulator escape-width routing blocker.
  • Set USB D+/D− nets to 0.15 mm trace width.
Remaining review issue: 4 USB D+/D− airwires at the USB-C connector/ESD path. A second cleanup routing pass added 0 nodes, so these likely need manual/targeted USB routing or a small USB connector/ESD placement adjustment.
L

louisb2acc

move the j2 to the top left edge but keep a clearance of around 0.73cm from the edge. same applies for the other compondtes already on the top edge make sure theres that 0.73cm clearance along that edge. move both switchs down to the bottom inbeween the esp32 and J1. also make the traces neat no lines going over ccomponets and also fix all the eroors theres cuts and deadends to the traces

flux

I’ll adjust the placement as requested, then remove stale/cut/dead-end traces caused by moving parts and rerun routing/review. I’ll keep J2 and the top-edge parts about 7.3 mm from the top edge, and move RST_SW/BOOT_SW down between the ESP32 and J1.

flux

I’m out of execution credits, so I had to stop after the placement step.
Completed:
  • Moved J2 to the top-left edge area with about 7.3 mm clearance from the board edge.
  • Adjusted the other top-edge components so they keep that same top-edge clearance.
  • Moved RST_SW and BOOT_SW down between the ESP32-S3 module and USB-C connector J1.
  • Preserved the ESP32 antenna orientation facing the bottom edge.
  • Placement now has no overlap or out-of-bounds issues.
Still to do:
  • Delete stale/dead-end traces created by moving components.
  • Re-route the affected nets.
  • Clean up trace paths so they don’t run awkwardly over/through component areas.
  • Rerun review and fix the remaining routing errors, including the USB D+/D− airwires.
Clean reroute traces
Run DRC review
Route USB pair
Check trace crossings
Sign up to send

Files

Schematic

Layout

3D View

Power Budget — ESP32 Relay Controller
Sources and Rails

Table

Source/RailVoltageFunction
External input12V DCPowers relay coil and buck regulator
Buck output3.3VPowers ESP32-S3 module
USB-C VBUS5V from hostData-port presence only; not tied to board power
Load Estimates

Table

RailLoadDatasheet / Design BasisCurrent
3.3VESP32-S3-WROOM moduleEspressif requires external supply capable of at least 0.5A500mA peak
12VACNM1112 relay coil12V, 225 ohm coil, 53.3mA rated53.3mA active
Buck Input Current Estimate
Assume AP63203 efficiency around 85% at the design peak.
  • 3.3V output power at 500mA: 3.3V x 0.5A = 1.65W
  • 12V input current for buck: 1.65W / (12V x 0.85) = 0.162A
  • Relay coil current: 0.053A
  • Total 12V active peak estimate: 0.215A
Component Sizing Decisions
  • 12V input terminal is rated far above the expected current.
  • AP63203WU-7 is a 2A fixed 3.3V buck regulator, comfortably above the 500mA ESP32 design peak.
  • Buck inductor target: 3.9uH, saturation current at least 2.7A, low DCR preferred. The schematic uses a configurable generic inductor because no exact verified library inductor was found.
  • Relay driver MOSFET is rated far above the 53.3mA coil current and works at 2.5V gate drive.
  • Flyback diode is a 1A Schottky, above the relay coil current.
Notes and Open Items
  • External dry-contact load voltage/current was not specified; relay contact rating is high, but PCB trace spacing and terminal rating should be confirmed before routing if switching more than low-voltage control signals.
  • If the 12V input may be noisy or remote, add input surge/reverse-polarity protection before final layout.

  • Sources and Rails

  • Load Estimates

  • Buck Input Current Estimate

  • Component Sizing Decisions

  • Notes and Open Items