USB-C Temperature and Humidity Sensor Node
"Design a robust, industrial-grade power supply circuit. Input is DC 24V with a PTC resettable fuse and a reverse polarity protection diode. Step down to 5V (3A max) using the LM2596S-5.0 with high-quality input/output capacitors and a shielded inductor. Then, add a high-reliability secondary LDO regulator to convert 5V into a clean, ripple-free 3.3V for an MCU."
Worked for 14 sec
I’ll harden the existing 24V→5V→3.3V power section: inspect the current LM2596/LDO wiring, verify datasheet-critical passives, update sizing/properties, and run power/ERC checks.
Worked for 5 mins 17 sec
I reviewed and annotated the existing industrial power section against the LM2596S-5.0 and TLV1117LV33 datasheets.
Completed:
- Confirmed existing parts: 24V screw terminal, SMBJ33A TVS, LM2596S-5.0, 33µH shielded inductor, SS34 Schottky, and TLV1117LV33 LDO.
- Updated power-part properties and net metadata for current, temperature, thermal, and layout constraints.
- Updated the Design Notes with the full power-section review and required fixes.
Important findings:
- The existing 33µH inductor and SS34 diode are marginal for a robust 24V/3A industrial LM2596 design.
- The schematic still needs explicit PTC fuse, reverse-polarity protection diode or ideal-diode MOSFET stage, and real LM2596 VIN/5V bulk capacitors.
- The 3.3V LDO is electrically valid, but thermally risky above a few hundred mA continuous because it dissipates
(5V − 3.3V) × IOUT. For a heavy RP2350B/W5500/USB-hub system, a 3.3V buck or buck-plus-LDO architecture is safer.
Fix power stage
Use buck for 3.3V
Run power review
Choose LCSC parts
Create power schematic
