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Project Specification
Project Overview
Bench-only V1 ESP32-S3 sensor/control board for an external Raspberry Pi 5 + IMX296 nasal-endoscopy reconstruction prototype. Status: Schematic remediation complete; ready for renewed review, not yet for PCB layout approval. This is not clinical equipment and is not approved for patient contact.
Intended Use
Debug-oriented phantom/bench testing. Raspberry Pi and camera remain external and separately powered. The board collects IMU and ToF data, controls illumination, and communicates with the Pi over a separate self-powered native-USB data connection.
Locked source and load contracts
  • Main power: dedicated compliant USB-C 5 V/3 A source and cable, maintaining at least 4.75 V at J1 under a 1.12 A design peak. The CC Rd resistors identify a sink but do not grant 3 A.
  • LED: exactly one white LED branch, Vf 2.8–3.6 V at 250 mA, cable under 30 cm with no more than 0.15 V drop. No series strings.
  • J8 expansion, J7 SYNC_SPARE and J6 EN/BOOT: short bench jumpers only; no long-cable, independent external drive or hot-plug operation.
  • Remote IMU and ToF SDA/SCL must not be externally driven while the board is unpowered because their USBLC6 protection arrays clamp to board 3V3.
Main features
  • ESP32-S3-WROOM-1-N16R8.
  • ICM-42688-P SPI IMU with independent remote CS and 10 kΩ INT1/INT2 pull-ups for default open-drain behavior.
  • External VL53L5CX-SATEL-compatible 3.3 V interface with configurable/DNP local I2C pull-ups.
  • TPS92620QDRRRQ1 channel 1 at 250 mA, hardware default OFF.
  • Separate J1 power and J2 USB-data ports.
  • J2 VBUS detection through FOD817B3SD optocoupler; active-low GPIO2 output.
  • Rail-less TI TPD2EUSB30 on native USB D+/D−.
  • TVS protection on remote IMU, ToF SDA/SCL/INT/LPn, UART and primary sync signals.
Power architecture
Diagram



  
    
  
  
    
  











J2 D+/D-; optically isolated VBUS presence

MIPI CSI










Dedicated USB-C 5 V/3 A J1
SMBJ5.0A + TPS259470 eFuse
Protected 5 V
LMR33630B 3.3 V buck
ESP32-S3 N16R8
ICM-42688-P
External VL53L5CX-SATEL
TPS92620 250 mA LED
Raspberry Pi
IMX296 camera
Corrected critical components
  • U2 LMR33630BDDAR: 3 A adjustable 1.4 MHz synchronous buck.
  • L1 Coilcraft XAL7030-222MEC, 2.2 µH: Isat 18.0 A at 30% typical inductance drop; thermal-rise references 10.0 A at 20 °C and 12.9 A at 40 °C.
  • C7/C11/C12/C23/C24 Murata GRM32ER71E226KE15L, 22 µF, 25 V, X7R, 1210. C11/C12/C23/C24 form a four-part output bank with 47.56 µF conservative estimated effective capacitance; C7 provides 11.89 µF conservative estimated effective input capacitance at 5 V.
  • D2/D9/D10/D11 TI TPD2EUSB30.
  • U6 onsemi FOD817B3SD.
Interfaces
  • J3 remote IMU: 3V3, GND, SCLK, MOSI, MISO, independent CS, INT1, INT2.
  • J4 ToF: 1.25 mm JST-GH; 3V3, GND, SDA, SCL, INT, LPn.
  • J5 LED: regulated output and GND under the locked LED-module contract.
  • J6 UART/debug; J7 sync; J8 bench expansion; J9 optional NTC.
  • TP16 is the digital active-low USB-host-VBUS presence signal.
Verification requirements before layout approval
  • Confirm no rail rise with J2 connected and J1 absent.
  • Confirm J1 source voltage remains >=4.75 V under design peak.
  • Confirm LED regulation at the maximum permitted Vf and harness drop.
  • Confirm IMU interrupt open-drain behavior and remote bus contention controls.
  • Confirm ToF/UART/sync operation through added protection.
  • Renew independent schematic review after these live changes.
Current check status
Fresh Flux ERC/passive/component checks report no unresolved open warnings or errors after remediation. PCB layout remains intentionally unstarted.

  • Project Overview

  • Intended Use

  • Locked source and load contracts

  • Main features

  • Power architecture

  • Corrected critical components

  • Interfaces

  • Verification requirements before layout approval

  • Current check status