RS-485 transceiver 3.3 V, half duplex
Half-duplex RS-485 / Modbus RTU port for a 3.3 V UART, with three drop-in transceiver alternatives from different manufacturers. One enable pin switches between transmit and receive; it is pulled down, so the port listens by default and never drives the bus at reset. Bus side protected with series resistors and a TVS diode array rated for the RS-485 common-mode range, with fail-safe bias on board and a jumper for the bus termination. Supply filtered with a ferrite bead.
Key specifications
- Supply 3.0–3.6 V
- Half duplex, up to 10 Mbps
- Bus termination on a jumper, fail-safe bias on board
- 3.3 V logic: receive, transmit and enable pins with series resistors
Design notes
- Enable low (default) = receive, high = transmit. The receive output is held high while transmitting, so the UART stays idle.
This block is not available yet. It is released once its checks are complete. Planned price: €29.
Planned package contents
KiCad 10 design block
Schematic and PCB layout fragment; symbols and footprints embedded
BOM (CSV)
Manufacturer part numbers and LCSC codes
Schematic PDF + README
Interface, specs, population options and design notes
3D models
STEP models of the special parts; standard parts use KiCad’s 3D library
template.yaml
Machine-readable interface and limits
PCB Composer
Get blocks like this one composed and routed into one board for your device, without opening KiCad. Quote within 24 h.
About PCB ComposerDevelopment status
| Block ID | 0160 |
|---|---|
| Block name | 0160-rs485-transceiver-3v3 |
| Version | 1.1 |
| Status | DRC clean – Schematic and layout pass the KiCad rule checks; not yet verified on hardware. |
| Open review items | 4 (0 blocking) |
| PCB layout | Rule-checked layout fragment |
| Format | KiCad 10 design block (schematic + PCB) |
| Last change | 2026-11-03 |
Interface
Hierarchical labels the block exposes to the rest of your design.
| Net | Direction | Description |
|---|---|---|
| +RS485_SUP | Power in | 3.3 V supply, filtered by a ferrite bead |
| RS485_RO | Output | Receiver output to the MCU UART RX, series resistor and pull-up |
| RS485_DI | Input | Driver input from the MCU UART TX, series resistor and pull-down |
| RS485_EN | Input | Driver enable, high = transmit; pulled down (receive by default) |
| RS485_A | Bidirectional | Bus line A (non-inverting), series resistor, TVS, bias to the supply, termination jumper to B |
| RS485_B | Bidirectional | Bus line B (inverting), series resistor, TVS, bias to GND |
FAQ
Which KiCad version do I need?
KiCad 10. The files are saved in the KiCad 10 format and are meant to be placed with KiCad’s Design Blocks feature (schematic block, then “Apply Design Block Layout” on the PCB).
Do I need the Circuit Issues part library?
No. Symbols are embedded in the schematic and footprints in the PCB, so the block opens on its own. Parts carry manufacturer part numbers and LCSC codes.
Is the layout production-ready?
The layout fragment passes the KiCad design rule check. Route it into your board and run DRC with your own fab rules.
Can I use the template in a commercial product?
The licence terms are published together with the first release.
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