What Is the MAX485? RS-485 Transceiver: Pinout and Uses
The MAX485 is a transceiver IC for RS-485 communication. Its differential A/B lines provide long-distance, noise-resistant, multi-drop serial communication (~2.5 Mbps, typically 32 nodes). The MCU UART connects to DI/RO and direction control to DE/RE; it is half-duplex. Long lines need 120 Ω termination.
The MAX485 is a transceiver IC for RS-485 communication. Its differential (A/B) lines provide long-distance, noise-resistant, multi-drop serial communication. For the concept, see what is UART.
What is the MAX485 used for?
Industrial automation, Modbus, long-cable sensor networks and systems where many devices talk on one line. Unlike RS-232 it scales to hundreds of metres and many nodes (typically 32). The MCU UART connects to the DI/RO pins, and direction control to the DE/RE pins.
MAX485 pinout (DIP-8)
| Pin | Function |
|---|---|
| 1 | RO (receiver output → MCU RX) |
| 2 | RE (receiver enable, active-low) |
| 3 | DE (driver enable, active-high) |
| 4 | DI (driver input ← MCU TX) |
| 5 | GND |
| 6 | A (differential line) |
| 7 | B (differential line) |
| 8 | VCC (+5 V) |
Being half-duplex, RE and DE are usually controlled together by one GPIO (high to transmit, low to receive).
Highlights
| Parameter | Value |
|---|---|
| Standard | RS-485 (differential A/B) |
| Speed | up to ~2.5 Mbps |
| Nodes | typically 32 (per line) |
| Supply | 5 V |
Limitations
- Half-duplex (no simultaneous send/receive); direction control (DE/RE) is required.
- On long lines, termination resistors (120 Ω) are needed at the ends.
- For 3.3 V use the MAX3485 version.
Equivalents and alternatives
- MAX3485: the 3.3 V version.
- SN75176 / SP3485: close equivalents.
- MAX232: for short-distance RS-232.
Find it in our catalog
Use the MAX485 search.