USB-C Wi-Fi BLE Sensor Node Design

flux

I set up the project and converged the schematic architecture, but I could not finish wiring because execution credits ran out.
Done so far:
  • Renamed the project to USB-C Wi-Fi BLE Env Sensor Node and updated the description.
  • Chose the core architecture:
    • MCU: ESP32-C3-MINI-1-N4
    • T/RH sensor: Sensirion SHT41-AD1B-R2
    • USB-C input connector: GCT USB4215-03-A
    • Input protection / power-path: TI TPS25940L eFuse for reverse blocking, OVP, UVLO, and OCP
    • 3.3 V regulator: TI TPS62821 buck converter instead of an LDO, because the ESP32-C3 radio peaks make a small 5 V → 3.3 V LDO thermally marginal
    • USB ESD: identified suitable USB data-line protection parts such as USBLC6-2SC6 / TPD2EUSB30A
  • Verified key datasheet constraints:
    • ESP32-C3-MINI-1-N4: 3.0–3.6 V supply, Wi-Fi TX peak up to about 350 mA, BLE TX peak up to about 340 mA, deep sleep about 5 µA, USB on GPIO18/19, strapping on GPIO2/8/9, GPIO9 needs pull-up.
    • ESP32 hardware guidance: use at least 500 mA-capable 3.3 V rail, EN must not float, recommended 10 kΩ + 1 µF RC on EN, USB series resistors 22/33 Ω, antenna keepout at board edge.
    • SHT41: 1.08–3.6 V, I2C, fixed 0x44 address, idle about 80 nA, measurement current about 320–500 µA.
    • TPS25940L: 2.7–18 V input, programmable UVLO / OVP / current limit, reverse current blocking, open-drain fault output.
    • TPS62821: 2.4–5.5 V input, 1 A output, 4 µA quiescent current, recommended 470 nH inductor, 4.7 µF input, 2×10 µF output, adjustable output via resistor divider.
Power-budget decision:
  • The node is comfortably under a 500 mA USB source on average, even with Wi-Fi active.
  • A simple LDO would dissipate too much heat during high-radio activity, so the buck converter is the correct choice for a consumer design.
What remains:
  • Add all components to the schematic.
  • Wire:
    • USB-C CC pull-downs
    • USB VBUS entry protection and ESD
    • TPS25940L thresholds / current limit network
    • TPS62821 feedback network and passives
    • ESP32-C3 support parts, boot/reset, USB resistors
    • I2C pull-ups and SHT41 decoupling
    • optional status LED / debug header
  • Run review/ERC and fix any issues.
  • Create project files with the power budget and bring-up notes.
If you want, I can continue from this exact architecture in the next run: ESP32-C3-MINI-1-N4 + SHT41 + USB4215-03-A + TPS25940L + TPS62821.
Add and wire power
Add debug features
Set protection limits
Document design notes
Run ERC review
No schematic yet

Talk to Flux to get started.

No files yet

Documents

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

    Assets

    No assets added.

    USB-C Wi-Fi BLE Env Sensor Node

    USB-C Wi-Fi BLE Env Sensor Node thumbnail
    Consumer USB-C environmental sensor node using a low-power Wi-Fi + Bluetooth MCU and digital temperature/humidity sensor. Powered from 5 V USB-C sink input with input protection including reverse blocking, OVP, UVLO, and overcurrent limiting, then regulated to 3.3 V for the radio and sensor.

    Properties

    Properties describe core aspects of the project.

    Pricing & Availability

    See prices from popular manufacturers for your project.

    Controls